Recent advances in alkylidene carbene chemistry

Alkylidene carbenes, also called alkenylidenes, are reactive intermediates in organic chemistry. Despite their high reactivity, they undergo a range of synthetically useful transformations, including highly chemo- and regioselective intramolecular 1,5 insertions into unfunctionalized C-H bonds with retention of absolute configuration. This review article covers current understanding of the structure and bonding of alkylidene carbenes, methods of generation including recent analogous chemistry displayed by metal vinylidenes, the various factors affecting chemo-, regio- and diastereoselectivity, and applications in target synthesis.