Highly diastereoselective synthesis of 2-azabicyclo[2.2.1]hept-5-ene derivatives: Bronsted acid catalyzed aza-Diels–Alder reaction between cyclopentadiene and imino-acetates with two chiral auxiliaries
作者:Xerardo García-Mera、José E. Rodríguez-Borges、M. Luísa C. Vale、Maria J. Alves
DOI:10.1016/j.tet.2011.06.097
日期:2011.9
The cycloaddition between protonated glyoxylate imines possessing two chiral auxiliaries, N-(S)- or N-(R)-1-phenylethyl and (−)-8-phenylmenthyl or (+)-8-phenylneomenthyl, and cyclopentadiene is described. The absolute configuration of all adducts formed was unequivocally assigned through NMR, specific optical rotation, and X-ray data of appropriated derivatives. Experimental results confirm the highly
描述了具有两个手性助剂N-(S)-或N-(R)-1-苯基乙基和(-)-8-苯基薄荷基或(+)-8-苯基新薄荷基的质子化乙醛酸亚胺与环戊二烯之间的环加成。通过NMR,比旋光度和适当衍生物的X射线数据明确分配了所有形成的加合物的绝对构型。实验结果证实了高度外切( -这些氮杂狄尔斯-阿尔德反应-选择性,被从(下午8点)的组合获得的单加合物- [R -PEA)和(8PNM) - (小号-PEA)。