Synthesis of optically active, unnatural α-substituted glutamic acid derivatives by a chiral calcium-catalyzed 1,4-addition reaction

The first catalytic asymmetric 1,4-addition reactions of azlactones with acrylic esters have been developed. A chiral coordinative calcium catalyst was found to be effective for these reactions, and the desired 1,4-adducts were obtained in good yields and enantioselectivities. The product was converted to the corresponding alpha-alkylated glutamic acid by acid hydrolysis. (C) 2010 Elsevier Ltd. All rights reserved.