Stereoselective synthesis of cis ring fused endo or exo octahydropyrindin-4-ones by imino-Diels-Alder reaction.

Abstract

The Diels-Alder reaction of trimethylsilylenolether of 1-acetylcyclopentene 1b with benzylideneaniline 2 , catalyzed by AlCl 3, occurred with high exo or endo selectivity, depending upon kinetic or thermodynamic control. MeOH/Et 3N treatment of the intermediate cycloadducts 3 and 4 gave stereospecifically the cis ring fused exo or endo octahydropyrindin-4 onex 5 and 6 while α,β unsaturated ketones 8 or 9 were formed after acidic treatment. Basic isomerization of 6 afforded the corresponding trans ring fused endo ketone 7 .