Bis-alkylation of dimetallated phenylsulfonylmethyl triflone. A n+1 annulation strategy for synthesis of cyclic vinyl sulfones.

Abstract

Bis-metallation of phenylsulfonylmethyl triflone 4b produces a geminal dianion which can be dialkylated to afford α-phenylsulfonyl triflones. Treatment of these compounds with DBU affords vinyl sulfones which can be isomerized to allyl sulfones.