Cross-coupling of nonstabilized aziridinylmagnesiums with alkylhalides catalyzed by Cu(I) iodide: a new synthesis of amines bearing a quaternary chiral center and an asymmetric synthesis of both enantiomers of the amines from one chiral starting material

Treatment of sulfinylaziridines, which were synthesized from 1-chloroalkyl p-tolyl sulfoxides and imines, with ethylmagnesium bromide gave nonstabilized aziridinylmagnesiums by a sulfoxide-magnesium exchange reaction. The cross-coupling of the aziridinylmagnesiums with various kinds of alkylhalides was realized in high yields by using Cu(I) iodide as a catalyst, and the reaction was found to be stereospecific. The coupling products were hydrogenated with Pd(OH)2 in alcohol to give the amines bearing a quaternary chiral center in quantitative yields. Synthesis of both enantiomers of the amines bearing a quaternary chiral center was realized starting from optically active (R)-chloromethyl p-tolyl sulfoxide in good overall yields with perfect asymmetric induction.