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.
