Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

Abstract

AbstractAn efficient synthetic method for the allylic sulfone 2 containing a conjugated triene moiety has been proposed involving i) coupling of allylic sulfones 4 with the C5 bromoallylic sulfide 5, ii) base‐promoted dehydrosulfonation in the presence of allylic sulfide, and iii) selective oxidation of the resulting trienyl sulfide to the corresponding sulfone. Total synthesis of lycopene starting from the C15 allylic sulfone 2b has been described, where the new C10 bis(chloroallylic) sulfone 11 proved to be a useful substitute for the C10 bis(chloroallylic) sulfide 3, which did not require the problematic chemoselective sulfur oxidation in a conjugated polyene.