摘要：

A number of cycloalkyl tosylates (4-, 5-, 6-, 7-, 8-, 9-, 11-, 12-, 13-, 14-, 15- and 17-ring members) have been synthesized and the rates of acetolysis measured at several temperatures in order to ascertain the effect of ring size on reactivity. The behavior of several brosylates (5-, 6- and 7-) was also examined. In the common rings, the cyclopentyl and cycloheptyl derivatives exhibit an enhanced reactivity attributed to the de-eclipsing of bonds in the ionization stage. On the other hand, the decreased reactivity of the cyclohexyl derivatives is attributed to an increase in bond opposition in the ionization stage. A further increase in reactivity is observed in the medium rings (8- to 12-) followed by a decrease in the large rings (13- to 17-) to rates of reactions similar to those observed in open-chain compounds. The maximum in reactivity in the medium rings is attributed to a relief of strain accompanying the loss of a bond in the ionization stage. For the strained rings (5- to 11-members) a simple relationship exists between the association constants for cyanohydrin formation and the rate constants for acetolysis of the tosylates.

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