Indium-Promoted Diastereo- and Regioselective Propargylation of Chiral Sulfinylimines

The reaction of different chiral imines 3 derived from aldehydes or ketones with the silylated propargyl bromide 4b under sonication in the presence of indium metal led mainly or exclusively to the formation of protected homopropargylamines 5 in a diastereoselective manner. Of special interest are the ketimine derivatives because the new stereocenter has a quaternary configuration. The selective deprotection of the two protecting groups, the silicon and sulfinyl moieties, was easily achieved by conventional methodologies.