Studies dealing with the alkylation-[1,3]-rearrangement reaction of some phenylthio-substituted allylic sulfones

A series of 2-(phenylthio)-3-(phenylsulfonyl)alkenes are easily metalated with n-butyllithium, and the resulting carbanion is regioselectively alkylated by alkyl halides in the α-position to give β,γ-unsaturated sulfones in high yield. These substituted phenylthio allyl sulfones undergo a 1,3-sigmatropic phenylsulfonyl shift by thermal, light-induced, and in some cases acid-catalyzed pathways. Rearrangement occurs where the product sulfone is thermodynamically more stable than the starting material. Cross-over experiments and inhibition studies suggest that the thermal/photochemical reaction occurs by a radical chain mechanism involving a phenylsulfonyl radical. Alkylation of the rearranged sulfones could also be performed under mild conditions. A sequential 1,3-rearrangement-cyclization reaction of 3-alkenyl-substituted allylic sulfones was also studied