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  • Abstract
  • Protocol
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Abstract

Alkene or olefin metathesis reaction, catalyzed by organometallic complexes, involves the redistribution of groups at each end of the C=C double bond to produce new alkene molecules. The reaction mechanism involves two stages, that are intermediate formation and catalytic cycle. Each stage consists of two key steps namely ring-forming [2 + 2] cycloaddition and ring-opening fragmentation.

The first stage involves the initiation of the reaction by [2 + 2] cycloaddition of the starting alkene to the metallocarbene complex. There are two possibilities of cycloaddition reaction. Each results in the formation of an unstable four-membered metallacycle complex.

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The fragmentation of each complex gives a metal alkylidene intermediate each with the corresponding parts of the starting alkene. These intermediates serve as the catalyst for the second stage of the mechanism.

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In the catalytic cycle, each metal alkylidene intermediate reacts parallely with the starting alkene via ring-forming cycloaddition and rin-opening fragmentation. The reactions generate a new recombined alkene, and an ethylene molecule with simultaneous regeneration of metal alkylidene for the next catalytic cycle.

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Protocol

Alkene metathesis occurs in two stages: Intermediate formation and catalytic cycle. Each stage comprises two steps: ring-forming [2 + 2] cycloaddition and ring-opening fragmentation.

In the first stage, the reaction is initiated by the [2 + 2] addition of the starting alkene to the metallocarbene complex.

There are two possible cycloadditions, each resulting in an unstable four-membered metallacycle complex.

The complexes undergo fragmentation to form corresponding metal alkylidene intermediates, each containing the resp.......

Disclosures

No conflicts of interest declared.

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