SHORT COMMUNICATION THE GRUNWALD-WINSTEIN TYPE CORRELATION FOR 2-CHLORO-2,4,4- TRIMETHYLPENTANE: A SIMPLE TERTIARY ALKYL CHLORIDE THAT SHOWS ESSENTIALLY LIMITING BEHAVIOUR IN SOLVOLYSIS

摘要

Evaluation of the rates of solvolysis of 2-chloro-2,4,4-trimethylpentane (4) in 17 solvents on the basis of the Grunwald-Winstein type equation [log(k/k_0) = lN_T+ mY_(Cl) + c] gives an excellent correlation with l= -0.01 ± 0.02 and m = 0.74 ± 0.01. The neopentyl group in 4 more effectively shields the rear side of the reaction center than the tert-butyl group in 2-chloro-2,3,3-trimethylbutane. The rate ratio between 4 and 2-chloro-2-methylpropane (3) at 25℃ is 275 in trifluoroethanol and predicted to increase to 950 in trifluoroacetic acid. The previous 4:3 rate ratio of 22 in 80% ethanol evidently underestimated the B-strain effect on the solvolysis rate of 4 by a factor of at least 40.