Abstract

Allylcarbinyl tosylate was found to solvolyze in 98% formic acid 3.7 times faster than n-butyl tosylate. Changes in the rate ratio with nucleophilicity of the solvent suggest different mechanisms for these solvolyses. The formolysis products of allylcarbinyl tosylate, when corrected for secondary rearrangements, were found to be virtually identical with those from cyclobutyl tosylate. Deuterium-labeling experiments indicated complete scrambling of the methylene groups in the ring-closed products. These results are interpreted in terms of formation of bicyclobutonium ion intermediates. The rate acceleration for formolysis obtained upon methyl substitution in the 3- and 4-positions and phenyl substitution in the 4-position have been measured and found to be as large as 4500 for the 4,4-dimethyl substituted allylcarbinyl tosylate. The nature of the initial solvolytic transition state is discussed; the results are shown to be inconsistent with formation of classical carbonium ion intermediates. 1,1,4,4-Tetrafluoro-1,3-butadiene has been shown by dipole moment studies to exist in the s-trans conformation. The F19-F19 spin-spin coupling constants for this compound were found to be very similar to those of bis-4,5(difluoromethylene)-cyclohexene and perfluoro-1,2-dimethylenecyclobutane. These results are discussed in terms of the mechanism of fluorine-fluorine spin-spin coupling. The dissociation constants of a series of methyl alkyl ketone cyanohydrins have been measured by nuclear magnetic resonance spectroscopy. The heats of solution of the ketones and the cyanohydrins in methanol have been measured. The effect of alkyl groups on the heats of solution have been shown to be unimportant in determining the observed dissociation constants of the cyanohydrins of these ketones.

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