One-pot synthesis of chiral β-hydroxysulfones from alkynes via aerobic oxysulfonylation and asymmetric reduction in MeOH/H2O

A highly enantioselective synthesis of beta-hydroxysulfones from inexpensive and readily available terminal alkynes and sodium sulfinates via a consecutive one-pot reaction in an aqueous medium under mild conditions is described. The intermediates, beta-keto sulfones, generated from an aerobic oxysulfonylation of terminal alkynes and sodium sulfinates catalyzed by an iron salt in MeOH/H2O (v : v = 3 : 1) at 50 degrees C, were subsequently reduced by a Ru-catalyzed asymmetric transfer hydrogenation with HCOONa as a hydrogen source. A variety of chiral beta-hydroxysulfones were obtained in good yields and up to 99.9% ee values. This one-pot process could be easily scaled up for gram-scale synthesis.