Name: preparation of a corannulene-functionalized hexahelicene by copper(i)-catalyzed alkyne-azide cycloaddition of nonplanar polyaromatic units
Uploaded: 2016-09-18T14:00:00.000+00:00
Duration: 9 min 35 s
Description: Watch this Scientific Journal Video about Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units at JoVE.com

This work was funded by the Spanish Ministerio de Econom&#236;a y Competitividad (CTQ 2013-41067-P). H.B. acknowledge with thanks a MEC-FPI grant.

1. 기능화 2,15-Dimethylhexahelicene <ol><li> 2,15-dimethylhexahelicene의 Dibromination <ol><li> 30 %가 벤조일 퍼 옥사이드 (BPO) (70 % 0.356 g (1.0 밀리몰) 2,15-dimethylhexahelicene에, 0.374 g (2.1 밀리몰)을 새로이 재결정 N의 -bromosuccinimide의 (NBS) 및 24 mg의 (0.07 밀리몰) 중량 체중 안정 화제로서 물). 자기 교반 막대 한 100㎖의 슈렌 크 플라스크를 놓고 모든 고체. 쉬 렌크 라인에 불활성 가스를 재충전 한 다음 가스 배출의 3주기에 의해 질소 분위기 하에서 넣습니다. </li><li> 사염화탄소 21 ㎖ (사염화탄소)를 추가합니다. 격렬하게 교반하면서 조심스럽게 용매 막대한 손실을 방지하기 위해 동일한 대피하여 용액 / 재충전 처리를한다 (단계 1.1.1) 탈기. </li><li> 환류 가열 (77 ℃)에서 4 시간 동안 오일 욕조 혼합물. 1 H 핵 자기 공명 (NMR)에 의해 반응을 확인한다. 3.7 ppm으로 4.0 ppm의 웃음과 이중선자민련이 나타납니다. 그룹 (그림 1) - 그들은 diastereotopic -CH 2의 존재를 나타냅니다. </li><li> 완성되면, 혼합물을 실온으로 냉각시키고, 진공하에 용매를 제거한다. 펌프의 오염을 방지하기 위해 액체 질소로 가득 찬 트랩을 설정합니다. </li><li> 디클로로 메탄 30 ㎖ (DCM)의 조를 재용 둥근 바닥 플라스크에 옮기고 물을 실리카겔 4 g과 혼합 (전형적으로 조 중량 5 배 추가). 회전식 증발기에서이 혼합물을 농축시킨다. </li><li> 같은 이동상 : 한편, 헥산 / 에틸 아세테이트 (5 ~ 95)을 미리 혼합의 SiO2 겔 칼럼 (길이 20cm 약 4.5 cm의 두께)를 채운다. 칼럼의 맨 위에 혼합물을 추가 한 다음 모래 (2cm)의 레이어를 추가합니다. </li><li> 조심스럽게 새로운 모바일 단계에 부어 (일반적으로 튜브 당 20 mL 및 예상되는 제품의 용출에 가까운 4 ㎖) 시험관에서 분수를 수집하여 크로마토 그래피를 수행합니다. 박층 크로마토 그래피로 분획을 확인이미지 UV 빛 아래 : 같은 이동상 (5 헥산 / 에틸 아세테이트 95)와 (TLC). 예상 생성물 (4B)는 회전 증발기에서 용매를 모두 분획물을 원 조합 오프 제거한 후 황색 오일로서 0.35 머무름 인자 (RF)로 용출한다. 334 mg의 (65 % 수율)을 수득한다. 주 : 모든 슈렌 기술 지금부터 널리 프로토콜의 대부분에서 이용 될 가열 및 컬럼 크로마토 설정하는 오일 욕의 사용은, 그들이 자세히 설명되지 않으며 단지 몇 주석 때 필요한 것 부여. </li></ol></li></ol><img alt="그림 1" src="/files/ftp_upload/53954/53954fig1.jpg" /> .도 1 H-NMR 스펙트럼 (500 MHz의, CDCl3 중)의 2,15 -dimethylhelicene (위)과 2 시간 후 촬영 나누어지는 새로운 신호, 2 -CH에 해당하는 -을.., 빨간색 원 (아래)에 묘사되는 <a href="https://www.jove.com/files/ftp_upload/53954/53954fig1large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> <ol start="2"><li> 2,15 - 비스 (아 지드 메틸) hexahelicene <ol><li> 2,15 비스 (브로 모 메틸) hexahelicene 및 나트륨 아자 이드 0.390 g (6 밀리몰) 0.103 g (0.2 밀리몰)을 단다. 마그네틱 바가 장착하고, 질소 분위기 하에서 넣고를 50㎖의 쉬 렝크 플라스크에 모두 고체를 놓는다. </li><li> 물 5.2 ㎖ (H 2 O)과 테트라 하이드로 퓨란 (THF)의 8.6 ml를 혼합하고 쉬 렌크 플라스크에 용매의 혼합물을 부어. 솔루션을 드가. </li><li> 3 시간 동안 환류 (65 °에 C)에서 열. 1 H-NMR로 반응을 확인합니다. -CH 2 - 신호는 3.75 ppm으로 (그림 2)으로 이동한다. </li><li> 그 후, 쿠혼합물을 실온으로 내려 L 진공하에 THF를 제거한다. H 2 O 50 ㎖로 희석 </li><li> 분별 깔때기에 혼합물을 전송하고 DCM 40 ml의 3 회 추출한다. 모든 유기 상을 합하고 순수한 H 2 O (50 ㎖)로 세척 하였다. </li><li> 2,15 비스 (azomethyl) hexahelicene 대응 RF = 0.38에서의 황색 오일을 수득 이동상으로 헥산 / 에틸 아세테이트 (85:15)를 사용하여 실리카 겔상에서 컬럼 크로마토 그래피에 의해 정제하여 (도 5b). 70 mg의 (80 % 수율)을 수득한다. </li></ol></li></ol><img alt="그림 2" src="/files/ftp_upload/53954/53954fig2.jpg" /> 그림 2 : 1 H-NMR 스펙트럼 (500 ㎒의 주파수 대역을, CDCl3 중) 4 나 (위) 및 분취 량의 3 시간 후 촬영(아래). 지방족 지역의 변화를합니다. <a href="https://www.jove.com/files/ftp_upload/53954/53954fig2large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> Corannulene 2. 기능화 <ol><li> Corannulene의 Monobromination <ol><li> corannulene 0.125 g (0.5 밀리몰), 새로 재결정 화하여 89 mg의 NBS (0.5 mmol) 및 금 (III) 클로라이드 수화물 17 mg의 무게. </li><li> 10 ㎖의 모든 화합물에 특별히 마그네틱 바가 장착 된 마이크로파 반응 설계된 후 2 구 둥근 바닥 플라스크의 도움을 질소 분위기에 넣고 바이알 놓는다. </li><li> 1,2- 디클로로 에탄 (DCE)와 가스를 제거 솔루션 7 ML을 추가합니다. </li><li> 금 염 입자를 분산시키기 위해 2 분간 상기 혼합물을 초음파 처리. </li><li> 2 시간 동안 100 ℃에서 마이크로파 반응기 내부 가열한다. </li><li> 완료되면, 둥근 바닥 플라스크에 미정 옮기고 ROTAR 용매를 제거하여Y 증발. </li><li> 이동상으로서 헥산을 사용하여 SiO2로 겔 컬럼 크로마토 그래피로 정제하여. 참고 Bromocorannulene (도 4a)의 Rf로 황색 고체로서 수득 = 0.38. 99 mg의 (60 % 수율)을 수득한다. 미 반응 corannulene (3A)를 회수하고, 추가 사용을 위해 저장 될 수있다. 그것은의 Rf에 나타납니다 = 0.29. </li></ol></li><li> Bomocorannulene 및 Ethynyltrimethylsilane의 소노 가시라 커플 링 <ol><li> bromocorannulene 49 mg의 (0.15 밀리몰), [의 PdCl 2 (DPPF)] 49,50 (1,1-&#39;bis (diphenylphsphino) 페로센,의 CuI의 3 밀리그램 (0.015 mmol)을 인 DPPF 11 밀리그램 (0.015 밀리몰) 무게. (51) </li><li> 자석 막대와 함께를 50㎖의 쉬 렝크 플라스크에 모든 고체를 넣고, 질소 분위기 하에서 넣고. </li><li> 트리 에틸 아민 (3 NET)의 5.0 ML을 추가하고, 혼합물을 탈기. </li><li> 마지막으로, ethynyltrimethylsilane 104 μL (0.75 밀리몰)를 추가합니다. </li><li> 2 분간 상기 혼합물을 초음파 처리금속염 입자를 분산. </li><li> 주기적인 초음파로 24 시간 동안 85 ℃에서 가열 된 금속 염의 침착을 방지한다. 참고 : 혼합 색상은 팔라듐 (0)의 존재를 나타내는, 곧 흑자로 전환. </li><li> 실온으로 냉각시키고, 진공에서 3 순 증발시켰다. </li><li> DCM 20㎖에 재용 헥산으로 용출하는 실리카 겔상에서 컬럼 크로마토 그래피에 의해 정제는도 5a에 대응하는 RF = 0.28에서의 황색 고체를 얻었다. 41 mg의 (78 % 수율)을 수득한다. 주 : 조은 DCM으로 셀 라이트 패드를 통해 여과되는 경우, 합리적인 순수한 샘플이 얻어 질 수 있지만 포스 핀 유도체가 완전히 제거되지 않는다. </li></ol></li><li> TMS 탈 보호에 의해 Ethynylcorannulene의 준비 <ol><li> 도 5a의 35 밀리그램 (0.10 mmol) 및 무수 불화 칼륨 7.3 mg의 (0.125 밀리몰)을 단다. </li><li> 자기 막대을 구비 한 50㎖의 슈렌 크 플라스크에 모든 고체를 놓고질소 분위기 하에서 넣을 거라고. </li><li> THF 4 mL 및 메탄올 (메탄올)의 4 ml를 혼합하고 쉬 렌크 플라스크에 혼합물을 부어. 철저하게 드가. </li><li> 실온에서 반응 불투명 필름을 덮어 빛으로부터 멀리 플라스크를 유지 할 수 있습니다. 3.48 ppm으로 보면 1 H-NMR로 반응을 확인합니다. 출현해야 -CCH에 대응하는 신호 (도 3). 참고 :이 화합물은 반응성이 쉽게 분해 터미널 알킨을지지하지만, 우리는 아래에서 설명하는 작업까지 동안 아무런 문제를 발견하지 못했다. 그것은 자연의 빛에 따라 실시 하였다. </li><li> 일단 완성, 진공하에 THF를 제거하고 분별 깔때기에 모든 것을 전송, 물 10 ㎖로 희석. </li><li> , DCM (3 × 15 ㎖)로 추출 마지막 황색 고체가도 6a에 대응 얻는 실온에서 회전식 증발기에서 둥근 바닥 플라스크에 모든 유기 상을 조합하고 농축시켰다. 27 mg의 (정량적 수율)을 수득한다. </li></ol></li></ol><img alt="그림 3" src="/files/ftp_upload/53954/53954fig3.jpg" /> 그림 3 :.. 1 H-NMR 스펙트럼 5 (위)와 6 (아래)의 (500 메가 헤르츠, CDCl3 중) -CCH 단일 빨간색 원에 도시되어 <a href="https://www.jove.com/files/ftp_upload/53954/53954fig3large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> 클릭 화학 3. 최종 조립 <ol><li> CuSO 4 아스코르브 산 나트륨 15.3 mg을 (0.035 밀리몰)의 5B, 6A 20.0 밀리그램 (0.073 밀리몰), 1.4 mg의 (0.007 밀리몰), 1.7 mg의 (0.007 밀리몰) · 5H 2 O 무게 </li><li> AM을 구비 한 50㎖의 슈렌 크 플라스크에 모든 고체를 놓고agnetic 바, 질소 분위기 하에서했습니다. </li><li> 3 H 2 O ㎖의 THF 12 ml를 혼합하고 쉬 렌크 플라스크에 혼합물을 부어. 철저히 탈기 용액. </li><li> 플라스크의 상부에 접속 된 콘덴서를 3 일간 65 ℃에서 열 주기적으로 온도를 조절하여 반응을 확인하고 용매를 교반 볼륨. 1 H-NMR로 반응을 확인합니다. 3.48 ppm에서의 신호는 사라집니다 및 7.27 ppm의에 티닐 corannulene의 소비 및 트리아 졸 장치의 존재를 나타내는 (그림 4)로 전환 될 수있다. </li><li> 완료되면, 진공하에 THF를 제거하고 분별 깔때기에 혼합물을 이송, 물 20ml로 희석 하였다. </li><li> , DCM (3 × 20 ​​㎖)로 추출 둥근 바닥 플라스크에 모든 유기 상을 합하고, 회전식 증발기에서 농축시켰다. </li><li> 그런가상에서 컬럼 크로마토 그래피에 의해 정제하여,이 겔, 헥산으로 용출 / 에틸 아세테이트 (1 : 1) RF 및 옅은 황색 고체를 수득 = 0.597에 대응. 27 mg의 (75 % 수율)을 수득한다. </li></ol><img alt="그림 4" src="/files/ftp_upload/53954/53954fig4.jpg" /> 그림 4 : 1 H-NMR 스펙트럼 (500 MHz의, CDCl3 중) 5 (b)의 (위), 6 (가운데)과 이일 (아래) 후 촬영 나누어지는 조에서 -CCH 신호의 실종을합니다.. <a href="https://www.jove.com/files/ftp_upload/53954/53954fig4large.jpg" target="_blank">하시기 바랍니다 이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a>

The authors have nothing to disclose.

최종 화합물 7 비평 아로마틱 전구체에서 6 단계 3 각 반응에서 중등도 아주 좋은 수익률 3 B 후 작성되었습니다. 이 경로에서 관찰 된 주요 제한은 모두 비평 아로마틱 화합물의 브롬화이었다. 그러나, 화합물 4의 경우, 무료 corannulene 중요한 양은 상기 용도로 회수 할 수있다. 4 (b)의 ?...

그들의 특별한 기하학, corannulene 및 helicenes 훨씬 평탄에서 구조를 채택하고 흥미로운 속성에 상승을 제공합니다. 지난 몇 년 동안 1-15 수 분자이다 인해, 탄소 나노 튜브와 풀러렌을위한 분자 수용체의 검색은 매우 활성 영역입니다 16-19 인해, 주로, 유기 태양 전지, 트랜지스터, 센서 및 기타 장치 재료로서의 응용 가능성에. 20-28 corannulene와 풀러렌과 모양이 뛰어난 보완이 설계의 목적으로 여러 연구자들의 주목을 받고있다 분산 힘에 의해 초분자 관계를 구축 할 수있는 분자 수용체. 29-39 상술 한 비평 아로마틱 화합물의 화학 완전히 평면 분자에 대해 기재 한 것과 유사하지만, 원하는 선택성 및 수율을 달성하기에 적합한 조건을 찾기 위해 때때로 어렵다. 40 </sup&gt;이 작품에서 우리는 모든 연구 실험실에서 발견 간단하고 일반적인 기술을 적용하여 좋은 수율 몇 단계의 세 폴리 방향족 단위를 갖는 분자 (7)의 합성을 제시한다. 이 용액 C 60 37 좋은 상호 작용을 확립 협공 같은 형태를 채용 할 수 있기 때문에, 분자는 매우 중요하다; 그리고 인해 입체 축선의 존재 키랄 ​​분자이다 helicene 링커에 높은 키랄 풀러렌 덕분에 대한 잠재적 인 수용체로서 연구 선을 열 수있다. 41-45은 그러나, 라 세미 helicene 본 작업에 사용된다. 상용화하지 않기 때문에,이 시점에서, 이들 수용체를 합성 할 수있는 유일한 제한은 helicenes 및 corannulenes의 제조이다. 그러나, 새로운 방법에 따라 그들이 합리적인 단기간에 적합한 양으로 얻을 수있다 46-48 다른 출판.

<table><tbody><tr><td>2,15-Dimethylhexahelicene</td><td>N/A</td><td>N/A</td><td>Prepared according to reference 5b,c in the main text.</td></tr><tr><td>Corannulene</td><td>N/A</td><td>N/A</td><td>Prepared according to reference 5a in the main text.</td></tr><tr><td>&lt;em&gt;N&lt;/em&gt;-Bromosuccinimide (NBS)</td><td>Sigma Aldrich</td><td>B8.125-5</td><td>ReagentPlus&amp;reg;, 99%. Recrystallized from hot water.</td></tr><tr><td>Benzoyl peroxide (BPO)</td><td>Sigma Aldrich</td><td>B-2030</td><td>~70% (titration). 30% water as stabilizer.</td></tr><tr><td>Sodium azide</td><td>Sigma Aldrich</td><td>S2002</td><td>ReagentPlus&amp;reg;, &amp;ge;99.5%.</td></tr><tr><td>Gold(III) chloride Hydrate</td><td>Sigma Aldrich</td><td>50778</td><td>puriss. p.a., ACS reagent, &amp;ge;49% Au basis.</td></tr><tr><td>Ethynyltrimethylsilane</td><td>Sigma Aldrich</td><td>218170</td><td>98%</td></tr><tr><td>[PdCl&lt;sub&gt;2&lt;/sub&gt;(dppf)]</td><td>N/A</td><td>N/A</td><td>Prepared according to reference 6 in the main text.</td></tr><tr><td>CuI</td><td>N/A</td><td>N/A</td><td>Prepared according to reference 7 in the main text.</td></tr><tr><td>KF</td><td>Sigma Aldrich</td><td>307599</td><td>99%, spray-dried.</td></tr><tr><td>(+)-Sodium L-ascorbate</td><td>Fluka</td><td>11140</td><td>BioXtra, &amp;ge;99.0% (NT).</td></tr><tr><td>Copper(II) Sulphate 5-hydrate</td><td>Panreac</td><td>131270</td><td>For analysis.</td></tr><tr><td>Carbon tetrachloride (CCl&lt;sub&gt;4&lt;/sub&gt;)</td><td>Fluka</td><td>87030</td><td>For IR spectroscopy, &amp;ge;99.9%.</td></tr><tr><td>Dichloromethane (DCM)</td><td>Fisher Scientific</td><td>D/1852/25</td><td>Analytical reagent grade. Distilled prior to use.</td></tr><tr><td>Hexane</td><td>Fisher Scientific</td><td>H/0355/25</td><td>Analytical reagent grade. Distilled prior to use.</td></tr><tr><td>Ethyl acetate</td><td>Scharlau</td><td>AC0145025S</td><td>Reagent grade. Distilled prior to use.</td></tr><tr><td>Tetrahydrofuran (THF)</td><td>Fisher Scientific</td><td>T/0701/25</td><td>Analytical reagent grade. Distilled prior to use.</td></tr><tr><td>1,2-Dichloroethane (DCE)</td><td>Sigma Aldrich</td><td>D6,156-3</td><td>ReagentPlus&amp;reg;, 99%.</td></tr><tr><td>Methanol (MeOH)</td><td>VWR</td><td>20847.36</td><td>AnalaR NORMAPUR.</td></tr><tr><td>Triethyl amine (NEt&lt;sub&gt;3&lt;/sub&gt;)</td><td>Sigma Aldrich</td><td>T0886</td><td>&amp;ge;99%</td></tr><tr><td>Silica gel</td><td>Acros</td><td>360050010</td><td>Particle size 40-60 mm.</td></tr><tr><td>Sand - low iron</td><td>Fisher Scientific</td><td>S/0360/63</td><td>General purpose grade.</td></tr><tr><td>TLC Silica gel 60 F&lt;sub&gt;254&lt;/sub&gt;</td><td>Merck</td><td>1.05554.0001</td><td></td></tr><tr><td>Monowave 300 (Microwave reactor)</td><td>Anton Para</td><td></td><td></td></tr><tr><td>Sonicator</td><td>Grupo Selecta</td><td>3000513</td><td>6 Litres.</td></tr></tbody></table>

preparation of a corannulene-functionalized hexahelicene by copper(i)-catalyzed alkyne-azide cycloaddition of nonplanar polyaromatic units

The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar polyaromatic units, which are two corannulene moieties and a racemic hexahelicene linking them. The compound described in this work is a good host for fullerenes. Several common organic reactions, such as free-radical reactions, C-C coupling or click chemistry, are employed demonstrating the versatility of functionalization that this compound can accept. All of these reactions work for planar aromatic molecules. With subtle modifications, it is possible to achieve similar results for nonplanar polyaromatic compounds.

Corannulene (3)과 2,15-dimethylhexahelicene (3 B)는 아주 좋은 수율 (그림 5)와 간단한 방식으로 현재의 방법을 46-48에 따라 제조 될 수있다. 두 최종 분자의 수렴 합성 발산 상승을주는 원료로서 일반적인 분자, 2,7- 디메틸 나프탈렌을 공유한다. <img alt="그림 5" src...

Watch this Scientific Journal Video about Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units at JoVE.com

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

여기서는 적당한 수율로 용이하게 조립 세 비평 폴리 방향족 단위로 이루어진 복잡한 유기 화합물을 합성하는 프로토콜을 제시한다.

구리 (I)에 의해 Corannulene 기능화 Hexahelicene의 제조 비평 아로마틱 유닛 알킨 지드의 고리 화를 촉매 반응

The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar ...

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Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

Aromatic Compounds

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11.4K 조회수.  Universidad de Valladolid.  여기서는 적당한 수율로 용이하게 조립 세 비평 폴리 방향족 단위로 이루어진 복잡한 유기 화합물을 합성하는 프로토콜을 제시한다. 

비디오: Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

The procedures described in this article involve the synthesis and isolation of hypervalent iodonium alkynyl triflates (HIATs) and their subsequent reactions with azides to form cyanocarbene intermediates. The synthesis of hypervalent iodonium alkynyl triflates can be facile, but difficulties stem from their isolation and reactivity. In particular, the necessity to use filtration under inert atmosphere at -45 &deg;C for some HIATs requires special care and equipment. Once isolated, the compounds can be stored and used in reactions with azides to form cyanocarbene intermediates. 
The evidence for cyanocarbene generation is shown by visible extrusion of dinitrogen as well as the characterization of products that occur from O-H insertion, sulfoxide complexation, and cyclopropanation. A side reaction of the cyanocarbene formation is the generation of a vinylidene-carbene and the conditions to control this process are discussed. There is also potential to form a hypervalent iodonium alkenyl triflate and the means of isolation and control of its generation are provided. The O-H insertion reaction involves using a HIAT, sodium azide or tetrabutylammonium azide, and methanol as solvent/substrate. The sulfoxide complexation reaction uses a HIAT, sodium azide or tetrabutylammonium azide, and dimethyl sulfoxide as solvent. The cyclopropanations can be performed with or without the use of solvent. The azide source must be tetrabutylammonium azide and the substrate shown is styrene.

Herein is described the synthesis, isolation, and reactions of hypervalent iodonium alkynyl triflates (HIATs) with azides to generate cyanocarbenes. The procedures will involve air-sensitive and cryogen techniques, including cold filtration under an inert atmosphere. Handling and safety of the synthesized compounds will also be discussed.

생성 Cyanocarbenes의 응용 프로그램에 대한 고원자가 요오드 알키 트라이 플레이트의 합성

The procedures described in this article involve the synthesis and isolation of hypervalent iodonium alkynyl triflates (HIATs) and their subsequent ...

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화학

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that derive from initial 2-bromo-2-butene lithiation followed by acid mediated dienol cyclization. The revised synthesis and purification of the ligand avoids the use of mechanical stirring while still permitting access to significant quantities (39 g) of Cp*H in good yield (58%). The procedure offers other additional benefits, including a more controlled quench of excess lithium during the production of the intermediate heptadienols and a simplified isolation of Cp*H of sufficient purity for metallation with transition metals. The ligand was subsequently used to synthesize [Cp*MCl2]2 complexes of both iridium and ruthenium to demonstrate the utility of the Cp*H prepared and purified by our method. The procedure outlined herein affords substantial quantities of a ubiquitous ancillary ligand support used in organometallic chemistry while minimizing the need for specialized laboratory equipment, thus providing a simpler and more accessible entry point into the chemistry of 1,2,3,4,5-pentamethylcyclopentadiene.

Reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented. The revised protocol for the synthesis and purification of the ligand minimizes the need for specialized laboratory equipment while simplifying reaction workups and product purification. Use of Cp*H in the synthesis of [Cp*MCl2]2 complexes (M = Ru, Ir) is also described.

가치있는 리간드에 액세스하면 전이 금속에 대한 지원 : 1,2,3,4,5-Pentamethylcyclopentadiene의 수정, 중간 규모 준비

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that ...

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the aziridine ring. The utility of bicyclic aziridinium ions, specifically 1-azoniabicyclo[3.1.0]hexane and 1-azoniabicyclo[4.1.0]heptane tosylate highlighted in the aziridine ring openings by the nucleophile with the release of the ring strain to yield the corresponding ring-expanded azaheterocycles such as pyrrolidine, piperidine and azepane with diverse substituents on the ring in regio- and stereospecific manner. Herein, we report a simple and convenient method for the preparation of the stable 1-azabicyclo[4.1.0]heptane tosylate followed by selective ring opening via a nucleophilic attack either at the bridge or at the bridgehead carbon to yield piperidine and azepane rings, respectively. This synthetic strategy allowed us to prepare biologically active natural products containing piperidine and azepane motif including sedamine, allosedamine, fagomine and balanol in highly efficient manner.

Bicyclic aziridinium ions such as 1-azoniabicyclo[4.1.0]heptane tosylate were generated from 2-[4-tolenesulfonyloxybutyl]aziridine, which was utilized for the preparation of substituted piperidines and azepanes via regio- and stereospecific ring-expansion with various nucleophiles. This highly efficient protocol allowed us to prepare diverse azaheterocycles including natural products such as fagomine, febrifugine analogue and balanol.

Azaheterocycles의 합성에 대 한 안정적인 Bicyclic Aziridinium 이온과 그들의 반지 개통 준비

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the ...

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

We present the chemoselective synthesis of 1-(iodoethynyl)-4-methylbenzene, 1-(1,2-diiodovinyl)-4-methylbenzene, and 1-methyl-4-(1,2,2-triiodovinyl)benzene as representative examples for the practical chemoselective preparation of 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes from the chemoselective iodination of terminal alkynes mediated by hypervalent-iodine reagents. The chemoselectivity was confirmed by using p-tolylethyne as a model substrate to screen a variety of iodine sources and/or the hypervalent-iodine reagents. A combination of tetrabutylammonium iodide (TBAI) and (diacetoxyiodo)benzene (PIDA) selectively generates 1-iodoalkynes, while a combination of KI and PIDA generates 1,2-diiodoalkenes. A one-pot synthesis based on both TBAI-PIDA and KI-PIDA yields the corresponding 1,1,2-triiodoalkenes. These protocols were subsequently applied to the synthesis of synthetically important aromatic and aliphatic 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes, which were obtained in good yield with excellent chemoselectivity.

Herein, detailed protocols for the oxidative iodination of terminal alkynes using hypervalent-iodine reagents are presented, which chemoselectively afford 1-iodoalkynes, 1,2-diiodoalkenes, and 1,1,2-triiodoalkenes.

1-Iodoalkynes, 1, 2-Diiodoalkenes, 및 1,1,2 Triiodoalkenes 터미널 Alkynes의 산화 Iodination에 따라 Chemoselective 준비

We present the chemoselective synthesis of 1-(iodoethynyl)-4-methylbenzene, 1-(1,2-diiodovinyl)-4-methylbenzene, and ...

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Protocols for the isolation of the commonly employed cyclic (alkyl)(amino) carbene (CAAC) and N-heterocyclic carbene (NHC) are reported. Furthermore, the synthesis of their mixed CAAC&#8211;NHC &#8220;Wanzlick&#8221; dimer and the synthesis of the related stable organic &#8220;olefin&#8221; radical are presented. The main goal of this manuscript is to give a detailed and general protocol for the synthetic chemist of any skill level on how to prepare free heterocyclic carbenes by deprotonation using filter cannulas. Due to the air-sensitivity of the synthesized compounds, all experiments are performed under inert atmosphere using either Schlenk technique or a dinitrogen filled glovebox. Controlling Wanzlick&#8217;s equilibrium (i.e., the dimerization of free carbenes), is a crucial requirement for the application of free carbenes in coordination chemistry or organic synthesis. Thus, we elaborate on the specific electronic and steric requirements favoring the formation of dimers, heterodimers, or monomers. We will show how proton catalysis allows for the formation of dimers, and how the electronic structure of carbenes and their dimers affects the reactivity with either moisture or air. The structural identity of the reported compounds is discussed based on their NMR spectra.

We present protocols for the isolation of stable heterocyclic carbenes. The synthesis of a cyclic (alkyl)(amino) carbene (CAAC) and an N-heterocyclic carbene (NHC) is demonstrated using filter cannulas and Schlenk technique. We furthermore present the synthesis of the related oxygen-sensitive, electron-rich mixed &#8220;Wanzlick dimer&#8221; and the reduced stable organic radical.

무료 Carbenes, 그들의 혼합 이합체 및 유기 급진 파를 격리

Protocols for the isolation of the commonly employed cyclic (alkyl)(amino) carbene (CAAC) and N-heterocyclic carbene (NHC) are reported. Furthermore, the ...

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

The conjugate addition of organometallic reagents to &#945;,&#946;-unsaturated carbonyls represents an important method to generate C&#8211;C bonds in the preparation of all-carbon quaternary centers. Though conjugate additions of organometallic reagents are typically performed utilizing highly reactive organolithium or Grignard reagents, organozinc reagents have garnered attention for their enhanced chemoselectivity and mild reactivity. Despite numerous recent advances with more reactive diorganozinc and mixed diorganozinc reagents, the generation of all-carbon quaternary centers via the conjugate addition of functionalized monoorganozinc reagents remains a challenge. This protocol details a convenient and mild &#8220;one-pot&#8221; preparation and copper mediated conjugate addition of functionalized monoorganozinc bromides to cyclic &#945;,&#946;-unsaturated carbonyls to afford a broad scope of all-carbon quaternary centers in generally excellent yield and diastereoselectivity. Key to the development of this technology is the utilization of DMA as a reaction solvent with TMSCl as a Lewis acid. Notable advantages to this methodology include the operational simplicity of the organozinc reagent preparation afforded by the utilization of DMA as a solvent, as well as an efficient conjugate addition mediated by various Cu(I) and Cu(II) salts. Moreover, an intermediate silyl enol ether can be isolated utilizing a modified workup procedure. The substrate scope is limited to cyclic unsaturated ketones, and the conjugate addition is impeded by stabilized (e.g., allyl, enolate, homoenolate) and sterically encumbered (e.g., neopentyl, o-aryl) monoorganozinc reagents. Conjugate additions to five- and seven-membered rings were effective, albeit in lower yields compared with six-membered ring substrates.

A simple and practical protocol for the efficient conjugate addition of functionalized monoorganozinc bromides to cyclic &#945;,&#946;-unsaturated carbonyls to furnish all-carbon quaternary centers was developed.

관 능 적 모노 아연 브로 미 데스의 결합체 첨가를 통한 전 탄소 4 급 센터의 효율적인 합성

The conjugate addition of organometallic reagents to &#945;,&#946;-unsaturated carbonyls represents an important method to generate C&#8211;C bonds in the ...

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Aziridines, a class of reactive organic molecules containing a three-membered ring, are important synthons for the synthesis of a large variety of functionalized nitrogen-containing target compounds through the regiocontrolled ring-opening of C-substituted aziridines. Despite the tremendous progress in aziridine synthesis over the past decade, accessing contiguous bisaziridines efficiently remains difficult. Therefore, we were interested in synthesizing contiguous bisaziridines bearing an electronically diverse set of N-substituents beyond the single aziridine backbone for regioselective ring-opening reactions with diverse nucleophiles. In this study, chiral contiguous bisaziridines were prepared by organocatalytic asymmetric aziridination of chiral (E)-3-((S)-1-((R)-1-phenylethyl)aziridin-2-yl)acrylaldehyde with N-Ts-O-tosyl or N-Boc-O-tosyl hydroxylamine as the nitrogen source in the presence of (2S)-[diphenyl(trimethylsilyloxy)methyl]pyrrolidine as a chiral organocatalyst. Also demonstrated here are representative examples of regioselective ring-opening reactions of contiguous bisaziridines with a variety of nucleophiles such as sulfur, nitrogen, carbon, and oxygen, and the application of contiguous bisaziridines to the synthesis of multi-substituted chiral pyrrolidines by Pd-catalyzed hydrogenation.

Contiguous bisaziridines containing non-activated and activated aziridines were synthesized by asymmetric organocatalytic aziridinations and then subjected to chemoselective ring-opening reactions under acidic or basic conditions. The non-activated aziridine ring opens with less reactive nucleophiles under acidic conditions, whereas the activated aziridine ring opens with more reactive nucleophiles under basic conditions.

위치 선택적 개환 반응을위한 연속 비사 지리딘의 제조

Aziridines, a class of reactive organic molecules containing a three-membered ring, are important synthons for the synthesis of a large variety of ...

Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most common drugs used to manage and treat pain and inflammation. In 2016, a new class of boron functionalized NSAIDs (bora-NSAIDs) was synthesized under mild conditions via the copper-catalyzed regioselective boracarboxylation of vinyl arenes using carbon dioxide (CO2 balloon) and a diboron reductant at room temperature. This original method was performed primarily in a glovebox or with a vacuum gas manifold (Schlenk line) under rigorous air-free and moisture-free conditions, which often led to irreproducible reaction outcomes due to trace impurities. The present protocol describes a simpler and more convenient benchtop method for synthesizing a representative bora-NSAID, bora-ibuprofen. A Suzuki-Miyaura cross-coupling reaction between 1-bromo-4-isobutylbenzene and vinylboronic acid pinacol ester produces 4-isobutylstyrene. The styrene is subsequently boracarboxylated regioselectively to provide bora-ibuprofen, an &#945;-aryl-&#946;-boryl-propionic acid, with good yield on a multi-gram scale. This procedure allows for the broader utilization of copper-catalyzed boracarboxylation in synthetic laboratories, enabling further research on bora-NSAIDs and other unique boron-functionalized drug-like molecules.

The present protocol describes a detailed benchtop catalytic method that yields a unique borylated derivative of ibuprofen.&#160;

Suzuki Cross-Coupling 및 Alkene Boracarboxylation 반응을 통한 Borylated Ibuprofen 유도체의 합성

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most common drugs used to manage and treat pain and inflammation. In 2016, a new class of ...

Preparation of Alkynes: Alkylation Reaction

<h4>Introduction</h4>
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
<img alt="Alkyne alkylation reaction using NaNH2 and ethyl bromide, chemical equation diagram." src="/files/ftp_upload/11834/11834_PT_Figure_1.svg" style="text-align: center; height: 50px;" data-altupdatedat="1747908711000" data-alt="Figure1">
The reaction takes place in two steps:
1. The first step is the deprotonation of the terminal alkyne by the strong base forming an acetylide ion.
<img alt="Alkyne ionization reaction equation NaNH2, diagram shows acetylene converting to acetylide ion." src="/files/ftp_upload/11834/11834_PT_Figure_2.svg" style="text-align: center; height: 50px;" data-altupdatedat="1747908711000" data-alt="Figure2">
2. The second step is a nucleophilic substitution reaction in which the acetylide ion reacts with the alkyl halide to form a new C–C bond.
<img alt="Organic reaction mechanism, Na+ and Br- ion exchange, illustrates chemical synthesis process." src="/files/ftp_upload/11834/11834_PT_Figure_3.svg" style="text-align: center; height: 50px;" data-altupdatedat="1747908711000" data-alt="Figure3">
<h4>Reaction Mechanism —SN2 pathway </h4>
Acetylide ions are strong bases and can also function as good nucleophiles. The substitution reaction follows an SN2 pathway where the nucleophilic acetylide ion attacks the electrophilic carbon of the primary alkyl halide from the backside.
<img alt="Nucleophilic substitution reaction mechanism diagram with alkynes, NaBr formation, chemical process." src="/files/ftp_upload/11834/11834_PT_Figure_4.svg" style="text-align: center; height: 250px;" data-altupdatedat="1747908711000" data-alt="Figure4">
Since this is a concerted process, the nucleophilic attack and the departure of the leaving group takes place simultaneously to form the product with an inverted stereochemistry at the reaction center.
The reaction works best with unhindered alkyl halides like methyl halide and other primary halides. With secondary and tertiary alkyl halides, acetylide ions act as strong bases, in which case E2 elimination is the preferred pathway.
<h4>Application in organic synthesis </h4>
Alkylation of simple terminal alkynes is a useful method to extend the length of the carbon chain. Acetylene, a terminal alkyne, can be converted to a higher internal alkyne by repeated alkylation as shown below:
<img alt="Alkyne chain elongation via NaNH₂, CH₃Br; reaction equation diagram for organic synthesis." src="/files/ftp_upload/11834/11834_PT_Figure_5.svg" style="text-align: center; height: 50px;" data-altupdatedat="1747908711000" data-alt="Figure5">

알카인의 제조: 알킬화 반응

Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for ...

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유기화학

Alkynes

주요 용어 및 개념

Preparation of Alkynes: Dehydrohalogenation

<h4>Introduction</h4>
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
<img alt="Chemical reaction diagram, alkyne synthesis, 2NaNH2/NH3, hydrogen elimination, organic chemistry." src="/files/ftp_upload/11835/11835_PT_Figure_1.svg" style="text-align: center; height: 200px;" data-altupdatedat="1747908711000" data-alt="Figure1">
<h4>Reaction Mechanism – E2 pathway</h4>
Vicinal dihalides
In the first elimination step, the strong base abstracts the proton from the dihalide that is oriented anti to the leaving group. Since E2 reactions follow a concerted pathway, the abstraction of a proton and departure of the halide leaving group occur simultaneously to form a haloalkene.
<img alt="Birch reduction mechanism diagram, showing electron flow in organic compound reaction." src="/files/ftp_upload/11835/11835_PT_Figure_2.svg" style="text-align: center; height: 90px;" data-altupdatedat="1747908711000" data-alt="Figure2">
In the second elimination reaction, another equivalent of the strong base reacts with the haloalkene in a similar fashion to give the desired alkyne.
<img alt="Elimination reaction mechanism diagram, E2 mechanism, showing alkene formation from alkyl halide." src="/files/ftp_upload/11835/11835_PT_Figure_3.svg" style="text-align: center; height: 90px;" data-altupdatedat="1747908711000" data-alt="Figure3">
Geminal dihalides
Likewise, geminal dihalides, when treated with two equivalents of a sodium amide, undergo double dehydrohalogenation to give alkynes.
<img alt="Alkyne formation reaction; sodium amide abstracting proton; chemical equation diagram; synthesis method." src="/files/ftp_upload/11835/11835_PT_Figure_4.svg" style="text-align: center; height: 90px;" data-altupdatedat="1747908711000" data-alt="Figure4">
<img alt="Chemical reaction mechanism, arrow-pushing diagram, alkyne formation using sodium amide." src="/files/ftp_upload/11835/11835_PT_Figure_5.svg" style="text-align: center; height: 90px;" data-altupdatedat="1747908711000" data-alt="Figure5">
Terminal dihalides 
Dehydrohalogenation of terminal dihalides yields terminal alkynes as the final product. In the presence of a strong base like sodium amide, terminal alkynes get converted to acetylide ions. In such cases, a third equivalent of the base is required to complete the dehydrohalogenation of the remaining haloalkene.
<img alt="Hofmann elimination reaction; chemical equations diagram; synthesis process using NaNH2; alkyne formation." src="/files/ftp_upload/11835/11835_PT_Figure_6.svg" style="text-align: center; height: 70px;" data-altupdatedat="1747908711000" data-alt="Figure6">
Protonation of the acetylide ions with water or an aqueous acid completes the reaction.
<img alt="Organic reaction mechanism with sodium acetylide, water; diagram illustrating nucleophilic attack." src="/files/ftp_upload/11835/11835_PT_Figure_7.svg" style="text-align: center; height: 50px;" data-altupdatedat="1747908711000" data-alt="Figure7">
<h4>Application in Organic Synthesis</h4>
Dehydrohalogenation of vicinal dihalides is a useful intermediate step in the conversion of alkenes to alkynes. For example, chlorination of 1-propene gives 1,2-dichloropropane – a vicinal dihalide, which upon double dehydrohalogenation yields 1-propyne.
<img alt="Alkene to alkyne conversion diagram; chemical reaction mechanism, dichlorination, dehydrohalogenation." src="/files/ftp_upload/11835/11835_PT_Figure_8.svg" style="text-align: center; height: 60px;" data-altupdatedat="1747908711000" data-alt="Figure8">
Similarly, alkynes can also be synthesized from ketones via dehydrohalogenation of geminal dihalides. For example, treatment of acetone with phosphorous pentachloride yields 2,2-dichloropropane – a geminal dihalide, which undergoes double dehydrohalogenation to give 1-propyne.
<img alt="Organic synthesis mechanism; ketone to alkyne via substitution and elimination; chemical reaction diagram." src="/files/ftp_upload/11835/11835_PT_Figure_9.svg" style="text-align: center; height: 80px;" data-altupdatedat="1747908711000" data-alt="Figure9">

알카인의 준비: Dehydrohalogenation

Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ...