Synthesis of 2-Acyl-2H-1,2,3-diazaphosphofes and Their Diels-Alder Reaction with Cyclopentadiene

摘要

2H-1,2,3-Diazaphospholes 3a — 3h were prepared from various ketone acylhydrazones and phosphorus trichloride in the presence of triethylamine. Compounds 3 underwent feasible hetero-Diels-Alder reactions with cyclopen-tadiene to afford the respective anellated [1,2,3]diazaphospholes 4a — 4d as well as 4a′— 4d′ in moderate yields. The endo rule in the reaction was observed under kinetic control conditions.