cis- and trans-Doubly bridged ethylenes via sigmatropic rearrangements. Synthesis of Cs- and C1-(±)-15-thiabicyclo[10.7.0]nonadec-1(12)-ene
Abstract
cis- and trans-Doubly bridged ethylenes result from the stereospecific [2,3]sigmatropic rearrangement of spirocyclic allylic sulphonium ylides.