Metal-mediated two-atom carbocycle enlargement in aqueous medium

Abstract

The indium and tin-mediated carbonyl allylations of 1,3-dicarbonyl compounds have been studied in aqueous medium. The study led to the development of a novel two-atom carbocycle-enlargement in water. Five-, six-, seven-, eight-, and twelve-membered rings are enlarged by two carbon atoms into seven-, eight-, nine-, ten-, and fourteen-membered ring derivatives respectively. Tetralone derivatives are similarly expanded to 6–8 fused ring systems; and indanone derivatives are expanded to 5–7 fused ring systems. The use of both indium and zinc as the metal mediators provided the ring expansion products successfully. The use of water as a solvent was found to be essential for the ring expansion reaction.