Etude Conformationnelle De 2,3,5,6,7,8-Hexahydro-4H-Benzopyranne-4-Ones, A L'Aide De La Mecanique Moleculaire

Abstract

The conformational study of 2,3,5,6,7,8-hexahydro-4H-benzopyran-4-ones, using molecular mechanics, shows that the more stable conformations contain a half-chair cyclohexenic ring and a half-chair strongly distorted toward a sofa form for the dihydropyran-4-one ring. The interconversion barrier of 3,4-dihydro-2H-pyran-4-one is lower than that for cyclohexene (5 versus 6.1 Kcal/mol). This work is ratified by reasonable correlation between experimental data and empirical force-field calculations.