Highly enantioselective reduction of meso-cyclic-1,2-dicarboximides. Asymmetric synthesis of bicyclic 2-pyrrolidinone and its 5-hydroxy congener

Bicyclic 5-hydroxy-2-pyrrolidinones (2a - f) were synthesized with high enantioselectivity by the reduction of meso-cyclic-1,2-dicarboximides (1a - f) with lithium aluminum hydride (LiAlH 4 )-methanol (MeOH)-1,1'-bi-2-naphthol complex (BINAL-H). Treatment of 2a - f with triethylsilane (Et 3 SiH) and trifluoroacetic acid(CF 3 CO 2 H) gave optically active 2-pyrrolidinones (3a - f) in quantitative yields. For the absolute configuration correlation, 2a - d were converted into known lactones (4a - d)