Oxa-ene reaction of enols of amides with 4-phenyl-1,2,4-triazoline-3,5-dione

摘要

[GRAPHICS] The reaction of 16 enols of amides with 4-phenyl-1,2,4-triazoline-1,3-dione gave open chain adducts rather than the [2 + 2] cycloadducts with a hemiaminal moiety, both in solid state and in solution. This assignment is based on X-ray crystallography, H-1 and C-13 NMR data, and IR spectra. The suggested mechanism involves hydroxyl proton loss in a formal oxa-ene reaction. Mechanistic details and a possible alternative are discussed.