Stereospecific [2,3] sigmatropic rearrangement of allylic sulfoxides and selenoxides. Synthesis of novel polycyclic allylic alcohols and α-hydroxy ketones

A stereospecific [2,3] sigmatropic rearrangement of functionalized bi- or tricyclic allylic sulfoxides and selenoxides as a route to new allylic alcohols and their transformation into the corresponding α-hydroxy ketones having a defined stereochemistry is described. It has been demonstrated that cycloadducts, derived from [4+2] cycloaddition of (Z)-1-alkylthio-2-diethoxyphosphoryloxy-1,3-dienes to a various dienophiles, are versatile synthons carrying much structural and stereochemical information.