Catalytic Use of a Soluble Organoindium(III) Species for Allylation and Crotylation of Ketones with Boronates

The unprecedented use of a soluble organoindium species, indium(III) hexamethyldisilazide [In(III)(hmds)(3)], for catalytic carbon-carbon bond formations between ketones and boronates, is reported. Various functionalized tertiary homoallyl alcohols were generated easily in high yields. Remarkably, free hydroxy and primary amine functionalities proved to be tolerated. A rate acceleration and markedly improved diastereoselectivities were observed in the presence of methanol. Based on preliminary NMR experiments and the alpha-selectivity with an alpha-substituted boronate, we assume the in situ generation of reactive allylindium(III) species through catalytic boron-to-indium transmetalation.