Michael additions of nitrogen heterocycles, thiols, carbon nucleophiles and amines to dehydroalanine derivatives, including a glycyldehydroalanine peptide, are performed in fair to good yields. Didehydroaminobutyric acid derivatives react only with the stronger nucleophiles but in considerably lower yields and often no reaction is observed with the corresponding didehydrophenylalanine derivatives. When a tosyl group is bonded to the nitrogen atom of the dehydroamino acid, in some cases the addition product undergoes elimination of this group and yields the corresponding β-substituted derivative of the α,β-didehydroamino acid. Addition of some β-dicarbonyl compounds leads to formation of products to which the structure of α,α-disubstituted cyclic amino acid derivatives is assigned.
氮杂环、
硫醇、碳亲核体和胺与脱
氨基丙酸衍
生物(包括甘
氨酸脱
氨基丙酸肽)进行的迈克尔加成反应,产率较好,达到中等到良好
水平。二脱
氨基
丁酸衍
生物仅与强亲核体反应,但产率明显较低,且通常在相应的二脱
氨基苯丙
氨酸衍
生物中未观察到反应。当托烯基(tosyl)基团连接在脱
氨基酸的氮原子上时,在某些情况下,添加产物会发生该基团的消除,生成相应的α,β-二脱
氨基酸的β-取代衍
生物。一些β,
β-二酮化合物的添加导致形成的产品被赋予α,α-二取代环状
氨基酸衍
生物的结构。