Rates of solvolysis and of base-catalysed elimination of substituted αα-dimethylphenethyl chlorides

Abstract

Rates of solvolysis in methanol, and of concurrent solvolysis and sodium methoxide-catalysed elimination in methanol, of substituted αα-dimethylphenethyl chlorides have been measured at 66·5°, and product distributions have been determined in these reactions. For solvolysis, log k₁ values correlate with σ° values and ρ=–1·15. The product distribution appears to be constant (∼50% ether, ∼30% conjugated olefin, and ∼20% non-conjugated olefin) when the substituent is varied. In elimination the conjugated olefin is the major product, and its proportion increases when electron-withdrawing substituents are introduced. For elimination to conjugated olefin ρ=+1·00 and for elimination to non-conjugated olefin ρ=–0·10. These results are not consistent with an E2 mechanism which has considerable E1 character, i.e., which has C–X bond fission much more advanced than C–H bond rupture in the transition state.