Iridium-Catalyzed Asymmetric Hydroalkynylation of Unactivated Alkenes

Key words

iridium catalysis - hydroalkynylation - enantioselectivity

Significance

The authors have developed an enantioselective iridium-catalyzed hydroalkynylation reaction. The reaction transforms trisubstituted β,γ-unsaturated amides with excellent γ-selectivity, forming new alkyne-substituted acyclic quaternary carbon stereocenters.

Comment

The kinetic isotope experiments of the alkenes resulted in an inverse KIE; suggesting that the migratory insertion of the alkene is related to the turnover-limiting step. Notably, the authors propose that the selectivity arises from both a facial preference as well as an alkene isomerization process.