Novel N–H Insertion Yields Amino Acids

Insertion of one reactant into a C–H bond of another reactant to form a chiral product is a valuable method in organic synthesis. The corresponding reactions involving X–H bonds, in which X is a heteroatom such as oxygen or nitrogen, have been much slower to develop. Last year, MIT's Gregory C. Fu and Thomas C. Maier reported the first efficient method for catalytic enantioselective insertions into O-H bonds, which involved merging aryldiazo esters into alcohols to form α–hydroxy carbonyl compounds. Using similar chemistry, Fu and Elaine C. Lee, also at MIT, now have moved on to enantioselective N–H insertions, merging aryldiazo esters into carbamates (represented as RNH₂) to generate α-amino acids as shown (J. Am. Chem. Soc., DOI: 10.1021/ja074483j). The new reaction, which complements two other recent examples of N–H insertions, could become a pathway for producing enantioenriched amino acids, they note.