Hydrolysis and Reversible Isomerization of Humulene Epoxides II and III

Article abstract of DOI:10.1021/jo00043a033

The hydrolysis reactions of humulene epoxide II (3) and humulene epoxide III (4) were studied on aqueous solution at pH 4.0.Twelve compounds from the hydrolysis of humulene epoxide II and 16 from humulene epoxide III were separated and identified.All of the compounds identified from hydrolyis of 3 also were found among the hydrolysis products of 4.A reversible transformation between these two epoxides proceeding through a bicyclic diol (15) as intermediate is responsible for producing the same products.Hydrolysis reactions further yielded diols and a number of different ring systems.The apparent intermediacy of carbocations also led to several elimination reaction products.Among the products identified from these epoxides, six have not been reported before.These are 1,5,8,8-tetramethyl-12-oxa-5-tricyclo<7.2.1.0.^6,9>dodecene (1), 4,8,11,11-tetramethyl-8-tricyclo<7.2.0.0^2,5>undecen-5-ol (5), stereoisomers of 2,6,6,9-tetramethyltricyclo<6.3.0.0^2,4>undecane-5,9-diol (10, 14), 1,5,8,8-tetramethyl-8-bicyclo<8.1.0>undecene-2,9-diol (15), and the stereoisomeric pair 4,8,11,11-tetramethyltricyclo<6.3.0.0^2,4>undecane-5,9-diol (16).