Unprecedented effects of achiral oxazolidinones on enantioselective radical-mediated conjugate additions using a chiral zinc triflate

[GRAPHICS] A role of achiral oxazolidinones to enhance the enantioselectivity in react ions of N-cinnamoyloxazolidinones with alkyl radicals promoted by a chiral Lewis acid Is described. Efficient enantioselective radical-mediated conjug ate additions of N-cinnamoyloxazolidinone can be realized by use of a chira l zinc triflate generated from a readily prepared chiral bisoxazoline and a n achiral oxazolidinone. The NH moiety of achiral oxazolidinones is found t o be necessary to enhance the enantioselectivity.