2,2-Azobis(2-methylpropiomtrile)-Mediated Alkyne Hydrostannylation: Reaction Mechanism

摘要

The hydrostannylation of alkynes to produce vinylstannanes of high regio- and stereochemical fidelity is a process of high importance in synthetic chemistry. Consequently, the mechanism of free-radical-mediated hydrostannylation has been intensively studied since it was first reported in 1968 by Leusink. All proposed hypotheses include one common feature: the process involves radical intermediates exclu-sively. On the surface, this is reasonable because the reaction is initiated by rather 2,2'-azobis(2-methylpropio-nitrile) (AIBN) or Et3B, both of which are well-estabhshed radical initiators. Unfortunately, this underlying central belief, upon which all understanding is built for this important transformation, appears not to be correct.