One or More CH, CC, and/or CC Bond(s) Formed by Rearrangement

Abstract

This chapter reviews rearrangement reactions that form a double bond and the period covered is 1995–2003. The reactions discussed have a broad scope and, although major emphasis is given to synthetic aspects, especially in the area of natural products synthesis, mechanistic (and computational calculations) and stereochemical features (including asymmetric catalysis) are also mentioned. The first section deals with the hydrogen migration reactions of different orders, [1,2]- and [1, j ]-, including sigmatropic, acid-, base-, and metal-catalyzed migrations of hydrogen. In the second section, the [1, j ]-rearrangements involving C -migration are collected, including sigmatropic reactions and the rearrangement of vinylcyclopropanes and vinylcyclobutanes. The [3,3]-sigmatropic rearrangements comprising the Cope rearrangement, and its different variants, thermal, photochemical, and catalyzed, are examined. The heteroatom versions: oxy-Cope (and anionic oxy-Cope), aza-Cope, oxonia-Cope are also included. The Claisen rearrangement and its different variants: Ireland–Claisen, Johnson–Claisen, Eschenmoser–Claisen, Carroll, thia-Claisen, aza-Claisen have also been examined. The final section provides information about tandem sigmatropic reactions and higher sigmatropic rearrangements, cyclopropane ring-opening reactions and epoxide rearrangements.