Science of Synthesis

Michalak, M.; Gułajski, Ł.; Grela, K., Science of Synthesis, (2010) 47, 332.

Given the various possible alkylidene intermediates and the numerous primary and secondary metathesis pathways involved in a cross-metathesis reaction, it is difficult to accurately predict how the complex interplay of steric and electronic factors will determine the ability of various sets of alkenes to participate in selective cross-metathesis reactions. Due to the multitude of factors influencing alkene reactivity in cross metathesis, a more straightforward, empirical ordering or categorization of the reactivity of an alkene is required. It has been proposed that the most convenient way to rank alkene reactivity is to examine their ability to homodimerize.[‌27‌] However, instead of simply looking at the absolute ability of an alkene to undergo homodimerization, it is better to look at its ability to undergo homodimerization relative to other alkenes and describe alkenes on a gradient scale of their propensity to undergo homodimerization, and importantly, the subsequent reactivity of their homodimers. This analysis[‌27‌] leads to a general model that comprises four distinct alkene types which can be used to predict both selective and nonselective cross-metathesis reactions.

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References

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• 8.Meeeee-Meee, (8888) 88/8e, 888.
• 8.Meeeee-Meee, (8888) 88/8e, 888.