Highly enantioselective construction of a quaternary carbon centre by the Pummerer-type reaction: a total synthesis of (–)-sibirine
Abstract
Highly enantioselective quaternary carbon formation (96% enantiomeric excess) is achieved by the Pummerer-type reaction of a chiral vinylic sulphoxide with allylmagnesium bromide; this method is applied to the synthesis of (–)-sibirine.