Science of Synthesis

Zeh, J.; Hiersemann, M., Science of Synthesis: Stereoselective Synthesis, (2011) 3, 347.

General Introduction

A sigmatropic rearrangement is characterized by a bond reorganization event in which a σ-bond migrates along a π-system in a concerted fashion. The σ-bond shift is generally classified by a numbering system that refers to the number of atoms involved; for instance, [3,3] indicates that the σ-bond moves along a π-system to a position that is three atoms away in each direction from the original point of connectivity. To demonstrate the utility of stereodifferentiating and C—C-connecting sigmatropic rearrangements in target-oriented syntheses, this section provides selective coverage of significant examples of the Claisen, Cope, and [2,3]-Wittig rearrangements.