| 摘要 |
PURPOSE:Cpds. I (R is acyl residue; COB is carboxyl or protected carboxy; X is H or nucleophile; Y is nucleophile; Z is a leaving gp., e.g. 2-(1R, 5S-3-phenyl7-oxo-4-2,6-diazabicylo[3,2,0] hepto-2-ene-6-yl)-3,4-dihydroxy-3-methylbutyric acid diphenylmethylester. |
