Palladium-catalyzed conjugate addition to electron-deficient alkynes with benzenesulfinic acid derived from 1,2-bis(phenylsulfonyl)ethane: selective synthesis of (E)-vinyl sulfones.

A new, selective method for the synthesis of (E)-vinyl sulfones is presence by palladium-catalyzed C-S bond cleavage/conjugate addition. In the presence of Pd(OAc)(2) and DMEDA (N(1),N(2)-dimethylethane-1,2-diamine), 1,2-bis(phenylsulfonyl)ethane underwent the C-S bond cleavage, followed by conjugate addition to numerous electron-deficient alkynes afforded the corresponding (E)-vinyl sulfones in moderate to good yields.