LAUSR

Cooperative catalysis enables the controlled synthesis of unnatural amino acids Amino acids are the building blocks of proteins, and chemists use these difunctional molecules for the laboratory synthesis of a wide variety of useful chiral frameworks (1). New and efficient methods for the synthesis of unnatural amino acids are always in demand to augment the numerous approaches that have been reported (2). On page 990 of this issue, Li et al. (3) report a strategy for the enantioselective synthesis of amino acids based on the cooperative action of an achiral transition-metal complex with a chiral hydrogen-bond donor to catalyze carbenoid insertions into the N–H bonds of aliphatic amines.