Modification of g-Aminobutyric Acid with Acylacetylenes: Stereoselective C-Vinylation of the Primary Adducts and Transformation to Acylpyridines

Primary N–C adducts of g-aminobutyric acid (GABA) to acylacetylenes undergo mild stereoselective C-vinylation by another acylacetylene molecule to afford (2E,4Z)-4-acyl-5-aminoalka-2,4-dien-1-one-type diadducts in 83–92% yields. The latter cyclize to acylpyridines in up to 89% yields with the C–N bond cleavage in the GABA moiety and elimination of g-butyrolactone.