Indium(0)-mediated Csp 3-S/O cross-coupling approach towards the regioselective alkylation of α-enolic esters/dithioesters: A mechanistic Insight

Abstract

We have reported an indium(0)-mediated Csp3-S/O cross-coupling approach that leads to the highly regioselective alkylation of α-enolic acetate/dithioacetate systems. This hetero cross-coupling reaction does not require additional co-catalyst or promoter, and the in situ generated organoindium species promotes the reaction by acting as the coupling partner of the α-enolic acetate/dithioacetate substrates. The excellent selectivity for C-, S-, or O-alkylation is solely dependent on the nucleophilic behavior of α-enolic acetate/dithioacetate systems. These results were further supported by DFT calculations of the relative electronic energies of the substrates and products as well as the activation barriers of the respective transformations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.