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Reactivity and Regiochemical Behavior of the 2,2-Difluorocyclopropylcarbinyl Cation:  A New and Improved Mechanistic Probe To Distinguish Radical and Carbocation Intermediates

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journal contribution
posted on 11.06.1999 by Feng Tian, Merle A. Battiste, William R. Dolbier
Acetolysis of 2,2-difluorocyclopropylcarbinyl tosylate (5) yields products derived from both SN1 and SN2 processes. Product identification and kinetic data indicated, as had been predicted computationally, that the cyclopropylcarbinyl−allylcarbinyl cationic rearrangement of 5 occurs simultaneously with its ionization and with regiospecific proximal bond cleavage to give products that formally derive from the 1,1-difluoro-3-butenyl cation with a rate constant that is 8.3 × 104 smaller than that of the parent cyclopropylcarbinyl tosylate and 1.8 times larger than isobutyl tosylate at 96.6 °C.