A novel stereoselective access to des-A B-aromatic corticosteroids via intramolecular cycloaddition reaction—potential intermediates for the synthesis of corticosteroids

Abstract

A short and stereoselective synthesis of protected des-A B-aromatic corticosteroids (3) and (23)via trans- 2,3,3a,4,5,9b-hexahydro-3β-isopropenyl-7-methoxy-3aβ-methyl-1H-benz[e]inden-3α-ol (13) and its methoxymethyl ether derivative (20), which were prepared by thermolysis of 3-[2-(1,2-dihydro-4-methoxybenzocyclobuten-1-yl)ethyl]-2,4-dimethylpenta-1,4-dien-3-ol (11) and its methoxymethyl ether (19), respectively, is described.