3.16 The Semipinacol Rearrangements

Abstract

Semipinacol rearrangement, as an important chemical transformation procedure, provides a very effective way for the construction of C–C bond and complex molecular skeletons. In light of the first edition of COS and a general and broad depiction of semipinacol rearrangement, i.e., ‘Mechanistically, all such processes share a common reactive species in which an electrophilic carbon center, including but not limited to carbocations, is vicinal to an oxygen-containing carbon and can drive the 1,2-migration of a C–C or C–H bond to terminate the process, generating a carbonyl group,’ the semipinacol rearrangement was categorized into five types according to the type of electrophilic carbon center involved in the reaction. Under each section, substrates scope, general migration patterns, and further applications in total syntheses are provided.