| 摘要 |
A novel intermediate for synthesizing 1,.beta.-alkyl-1-carbapenem, i.e., 4,.beta.-(1.beta.-alkyl-2-carboxyprop-2-enyl)azetidin-2-one ( II ), is prepared stereoselectively by treating 4-(leaving group substituted)azetidin-2-one ( I ) with trans-2-(leaving group substituted)methyl-3-alkylacrylic acid ( III ) and a reducing metal. (see fig. I) wherein, R1 is hydrogen, alkyl, or substituted alkyl; R2 is optionally substituted alkyl; R3 is hydrogen or a carboxy-protecting group; and R4 and R5 each is a leaving group.
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