Synthesis of sesquiterpenes via silicon-guided rearrangement of epoxydecalins

Abstract

A survey of the rearrangement of methyldecalins via C-5 carbocation intermediates, with special attention to the silicon-guided rearrangement of epoxydecalins is provided. A TMS group properly positioned on either C-1 or C-9 promotes the acidic rearrangement of 10-methyl-4,5-epoxydecalins and 10-methyl-5,6-epoxydecalins with exclusive migration toward C-5 of the methyl or methylene groups linked directly to C-10. The application of this biomimetic approach to the synthesis of a number of spirocyclic and eremophilane sesquiterpenes is reported.