Asymmetric reduction of a carbon–nitrogen double bond: enantioselective synthesis of 4,5-dihydro-3H-2,3-benzodiazepines

Abstract

A highly specific enantioselective reduction, elaborated for the reduction of the 3,4-carbon–nitrogen double bond of 4-methyl-7,8-methylenedioxy-1-(4-nitrophenyl)-4,5-dihydro-3H-2,3-benzodiazepine 4 made possible the synthesis of the enantiomers of the potent non-competitive AMPA/kamate antagonists 2a, b. NMR Investigations of the reducing complex show that there is no formation of an 1,3,2-oxazaborolidine ring as may have been presumed on the basis of literature data.