Copper-Catalyzed Asymmetric N-H Insertions

Significance

A copper-catalyzed asymmetric insertion of α-diazo esters into the N-H bond of carbamates is described using a chiral bis(oxazoline) ligand. A variety of aryl groups are tolerated as substituents on the diazo ester, and the methodology is described for both Boc- and Cbz-protected amines. The products are valuable α-amino acids and are produced in good yields and enantioselectivities. A competition study shows that N-H insertion is preferred over N-D insertion.