摘要：

A series of alkyl and alkenyl methyl sulfones was subjected to deuterioxide-catalyzed exchange in deuterium oxide-dioxane solvent at 25°. The results are summarized in Table I. It was shown that 2-hydroxyhexyl methyl sulfone was stable to these exchange conditions. From these results the following conclusions may be drawn. (1) Increased alkyl substitution at a carbon adjacent to a sulfone substituent strongly retards the rate of carbanion formation relative to similar substitution changes in nitroalkanes and ketones. (2) The rate of exchange of an -SO2CH3 site is little affected by the other hydrocarbon group attached to a sulfone substituent whether it be alkyl, 1-alkenyl, or 2-alkenyl. (3) Alkyl-substituted allyl anionic species generated adjacent to a sulfone group undergo very specific protonation at the site next to the sulfone group. The difference in activation energies for the two protonation reactions is larger than the difference in ground-state energies of 1- and 2-alkenyl methyl sulfones. (4) Replacement of hydrogen on a carbon adjacent to a sulfone group by a 1-pentenyl substituent increases the rate of base-catalyzed deuterium exchange by a factor of 10. Replacement of n-propyl by 1-pentenyl causes a 104 increase in rate of exchange. (5) 1-Alkenyl methyl sulfones undergo most rapid exchange at the α-methyl position. The α-vinyl hydrogen is exchanged, by a protonion mechanism, somewhat more rapidly than reaction occurs at the allylic site. (6) Little difference is seen in the reactivities of cis- and trans-1-alkenyl methyl sulfones or in the reactivities of cis- and trans-2-alkenyl methyl sulfones.

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