Catalytic Enantioselective Synthesis of β2-Amino Acids This work was supported by the National Science Foundation (CHE 0092490) and the National Institutes of Health (GM57425).

A very direct approach for the synthesis of β-amino esters is provided by catalytic asymmetric CH activation by means of carbenoid-induced CH insertion (see scheme; Boc=butyloxycarbonyl; TFA=trifluoroacetic acid). The reactions described herein represent the first regioselective intermolecular CH insertions occurring at a methyl site.