A Retro-Diels-Alder Approach to Oxazoles and Imidazoles

Article abstract of DOI:10.1021/jo00064a029

Heating N-acyl derivatives 4 of 3-endo-aminobicyclo<2.2.1>hept-5-en-2-endo-ol (3) at 185-195 deg C for 4-5 h provides oxazoles 1a-e in 49-88percent yields.The reaction proceeds via an initial dehydration to an oxazoline which undergoes retro-Diels-Alder reaction to provide the oxazole.Similarly, imidazoles 7a-f may be obtained in 40-79percent yields by heating imidazolines 6a-f to effect the cycloreversion.