1995 年 53 巻 6 号 p. 518-529
The importance of the stereodivergent synthesis of both enantiomers of β-lactams is ever increasing in connection with the structure-activity relationship study and the development of new derivatives in the β-lactam antibiotics. In this account stereocontrol at the C-3 and C-4 carbons of β-lactams using metal ester enolate-imine condensation reactions is discussed. The addition of an achiral ester enolate with a chiral imine possessing a dioxolane ring derived from (2S, 3S)-1, 4-dimethoxy-2, 3-butanediol as a chiral auxiliary is presented, in which 4-monosubstituted, 3, 4-disubstituted, and 3, 3, 4-trisubstituted β-lactams are prepared in a highly stereodivergent manner simply by switching metal ester enolate species. The application to the stereoselective synthesis of 1β-methylcarbapenem from 4-monosubstituted β-lactam is conducted by the use of selective hydrogenation reaction as a crucial step. The addition of an achiral ester enolate with a chiral imine having an auxiliary derived from phenylglycine at the nitrogen and the reaction of a chiral ester possessing arylsulfinyl group as an auxiliary at the α-position to the carbonyl with an achiral imine are also described for the stereodivergent synthesis of each of β-lactams from a single chiral source.