Catalytic Dehydrogenative Stannylation of C(sp)-H Bonds Involving Cooperative Sn-H Bond Activation of Hydrostannanes

The catalytic generation of a stannyliumion-like tin electrophile by heterolytic cleavage of the Sn-H bond in hydrostannanes at the Ru-S bond of Ohki-Tatsumi complexes is reported. Reacting these activated hydrostannanes with terminal acetylenes does not lead to hydrostannylation of the C-C triple bond but to dehydrogenative stannylation of the alkyne terminus. The scope of this rare direct C(sp)-H bond stannylation with hydrostannanes is broad, and a mechanism involving a beta-tin-stabilized vinyl cation likely having a bridged structure is presented.