Stable configuration of ester-stabilized azomethine ylides is found to depend upon the substituent on the ylide nitrogen. Thus, N-substituted azomethine ylides derived from N-substituted 2-aminoacetates and carbonyl compounds undergo cycloaddition with olefinic dipolarophiles predominantly in anti forms, while N-protonated (or N-unsubstituted) azomethine ylides generated from 2-iminoacetates exclusively in syn forms.
稳定的酯稳定的
亚胺亚胺盐的构型发现取决于
亚胺氮上的取代基。因此,源自N-取代的2-
氨基
醋酸酯和羰基化合物的N-取代
亚胺亚胺盐与烯烃性偶极体的环加成主要以反式形式进行,而由2-亚
氨基
醋酸酯生成的N-质子化(或N-未取代)
亚胺亚胺盐则完全以顺式形式出现。