Regioselective lipase-catalysed amidation of dicarboxylic N-blocked amino acid diesters - Effect of the side-chain length

Diethyl esters of both (R)- and (S)-N-blocked alpha-aminoadipic and alpha-a minopimelic acids yield exclusively the omega-monoamide when they are subje cted to amidation catalysed by the lipase B of Candida antarctica in anhydr ous diisopropyl ether. These results are in contrast to the alpha-monoamide yielded by the equivalent L-glutamic derivatives under the same experiment al conditions. These results show that the length of the side chain plays a crucial role in the regioselectivity of the reaction.