F. Bickelhaupt, M. Newcomb, Christopher B. DeZutter
Dec 1, 2008
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0
Influential Citations
5
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Journal
European Journal of Organic Chemistry
Abstract
The reaction of 2-chloro-1,1,1-triphenylethane (1) with magnesium in THF has been reinvestigated. The reaction produced a dark-red solution and after deuterolysis with D2O, 1,1,1-triphenylethane (2; 16 %), 2-D-1,1,1-triphenylethane (3; 52 %) and 1,1,2-triphenylethene (4; 26 %) were isolated. Rate constants for phenyl migration in the 2,2,2-triphenylethyl radical were measured directly between 23 °C and 55 °C; the reaction is described by log k = 11.2 – 7.5/2.3 RT [kcal/mol] and the rate constant for rearrangement at 20 °C is 4.0 × 105 s–1. The combined results support the intermediate formation of radicals in the reaction of chloride 1 with magnesium. The red colour of the reaction mixture, however, indicates the formation of a carbanionic species, which has not yet been identified. The diffusion model for Grignard formation reactions of Garst et al. is in line with the product distribution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)