The influence of the nitro-group upon side-chain reactivity. Part V. The rate-determining α-proton extraction from 4-nitrobenzyl chloride and 3-methyl-4-nitrobenzyl chloride in their base-catalysed interaction with their corresponding aldehydes to form epoxides

Abstract

The fast and reversible base-catalysed α-proton extraction from 4-nitrobenzyl chloride (A) and from its 3-methyl derivative (B), followed by rate-determining carbene formation to give stilbene from the conjugate base, is changed to a rate-determining step if the reaction is carried out in the presence of a reactive aldehyde. This is then followed by a faster attack of the conjugate base on the aldehyde to give cis- and trans-epoxides. A direct comparison of the rates of α-proton extraction from (A) and (B) thus became possible.