Syntheses and Equilibrations of 6- and 7-Carbomethoxy-trans-2-oxadecalins

Article abstract of DOI:10.1021/jo00215a001

Syntheses of the title compounds based on a Robinson annulation scheme utilizing tetrahydropyran-4-one are described.The 6-substituted system is elaborated by using Wittig methodology, while the 7-substituted ester is prepared via regioselective enolate formation.The regioselectivity of the latter is verified by preparation of a 5-isomer by reductive carboxylation of the original annulation product.Base-catalyzed equilibrations indicate a slightly preference for the equatorial position than in the 2-decalyl analogue, with entropy contributing little to theconformational free energies.