4-oxo-pipecolic acid derivatives were obtained by double asymmetric induction aza-Diels–Alder reactions between chiral glyoxylate N-phenylethylimines and Danishefsky's diene mediated by zinc iodide. The key to success was the use of iminoacetates possessing two chiral auxiliaries, N-(S)- or N-(R)-1-phenylethyl and (−)-8-phenylmenthyl or (+)-8-phenylneomenthyl. Adducts were formed in good yields (78–81%), with complete
对映体纯的4-氧代-
哌酸衍
生物是通过
碘化锌介导的手性
乙醛酸N-苯基乙基
亚胺与Danishefsky's二烯之间的双重不对称诱导aza-Diels-Alder反应获得的。成功的关键是使用具有两个手性助剂N-(S)-或N-(R)-1-苯基乙基和(-)-8-苯基薄荷基或(+)-8-苯基
新薄荷基。加合物形成的收率高(78-81%),具有完全的区域选择性和高的非对映选择性(87-96%)。通过NMR,比旋光度和适当衍
生物的X射线数据明确地确定了形成的加合物的绝对构型。这些环加合物可以用作
生物活性
哌啶氮杂糖和
胡椒酸衍
生物的前体。