Structure and Reactivity of Small Ring Compounds. I. Solvolyses of Spiro[2,4]hept-4-yl and Spiro[2,5]oct-4-yl 3,5-Dinitrobenzoates

The solvolyses of spiro[2,4]hept-4-yl, spiro[2,5]oct-4-yl,2-methylenecyclopentyl, 2-methylenecyclohexyl, 2,2-dimethylcyclopentyl, and 2,2-dimethylcyclohexyl 3,5-dinitrobenzoates have been examined in 60 wt% aqueous dioxane. The solvolysis rate of spiro[2,4]hept-4-yl 3,5-dinitrobenzoate was 850 times greater than that of the corresponding allyl derivative, the 2-methylenecyclopentyl ester, and 3.0×105 times greater than that of the 2,2-dimethylcyclopentyl ester. Similarly, in the cyclohexyl series, spiro[2,5]oct-4-yl 3,5-dinitrobenzoate solvolyzed 330 times faster than the 2-methylenecyclohexyl ester and 1.9×105 times faster than the 2,2-dimethylcyclohexyl ester. In a buffered solution, the spiro[2,4]heptyl ester gave a mixture of spiro[2,4]heptan-4-ol (46%), bicyclo[3,2,0]heptan-1-ol (28%), and 3-methylenecyclohexanol (10%), besides internally-returned 3,5-dinitrobenzoate of bicyclo[3,2,0]heptan-1-ol (12%). Under the same conditions, the spiro[2,5]oct-4-yl ester produced spiro[2,5]octan-4-ol (71%), bicyclo[4,2,0]octan-1-ol (21%), and 3,5-dinitrobenzoate of bicyclo[4,2,0]octan-1-ol (6%), the product of internal return. The implication of these results are discussed.