Enantioselective radical alkynylation of C(sp(3) )-H bonds using sulfoximine as a traceless chiral auxiliary.

Enantioselective alkynylation of C(sp(3) )H bonds adjacent to a nitrogen atom has been achieved using only chiral p-tolyl tert-butyldimethylsilylethynyl sulfoximine and benzophenone under photo-irradiation conditions. A two-carbon alkyne unit was chemo- and enantioselectively transferred at the nitrogen-substituted methylene to produce the optically active propargylic amines of various structures. Remarkably, the NH-unprotected sulfoximine group efficiently transmits its stereochemical information to the product and functions as a traceless chiral auxiliary.