咪唑催化磷酰化丝、苏氨酸及其酯的活化反应

Reactions of N-Phosphoryl Serine and Threonine and Their Esters Catalyzed by Imidazole

咪唑对磷酰化氨基酸的活化反应具有较强的催化作用，磷酰化丝、苏氨酸在咪唑催化下不仅能发生溶剂解反应，如磷上酯交换、羧基活化成酯、成肽及磷酰基的Ｎ→Ｏ迁移等，而且还会发生分子内环化反应；对于化学性质非常稳定的磷酰化丝、苏氨酸酯在咪唑催化下也会发生上述反应；反应机理推测为丝、苏氨酸的侧链基团羟基在咪唑的存在下亲核进攻磷原子形成五配位中间体。

N-phosphoryl amino acids could be catalyzed by imidazole to result in solvolysis such as ester exchanges on phosphorus, esterification, formation of peptides and N→O migration of the phosphoryl group. For serine and threonine, a phosphaoxazole product was also detected. Only N-phosphoryl serine and threonine methyl esters were catalyzed by imidazole, A new type of pentacoordinate phosphorus intermediate was proposed.