The reaction of secondary α-amino acids with carbonyl compounds. Properties of the intermediate azomethine ylides. Oxazolidine formation versus 1.4-prototropy.
作者:Moustafa F. Aly、Harriet Ardill、Ronald Grigg、Stephanie Leong-Ling、Shuleewan Rajviroongit、Sivagnanasundram Surendrakumar
DOI:10.1016/s0040-4039(00)96868-0
日期:1987.1
Cyclic secondary α-amino acids react regiospecifically, via antidipole formation, with aldehydes bearing electron withdrawing substituents to give oxazolidines in good yield. In certain cases structural features in the α-amino acid promote a 1,4-prototropic process in the intermediate azomethine ylide and divert the reaction to give 2-pyrrolines, whilst use of ninhydrin as the carbonyl component results
环状仲α-氨基酸通过反偶极形成,与具有吸电子取代基的醛发生区域特异性反应,从而以高收率得到恶唑烷。在某些情况下,α-氨基酸的结构特征会促进中间体甲亚胺基叶立德中的1,4-质子交换过程,并使反应转移为2-吡咯啉,而在有利的情况下,使用茚三酮作为羰基组分可稳定甲亚胺基化物。