Alkyl–oxygen fission in carboxylic esters. Part XVII. Influence of the methoxyl and ethoxyl groups on the reactivity of 1-(1-naphthyl)ethanol and 1-(2-naphthyl)ethanol

Abstract

1-(1-Naphthyl)- and 1-(2-naphthyl)-ethanol and their carboxylic esters react by a mechanism which involves alkyl–oxygen fission. However, the esters tend to undergo alkyl–oxygen fission less readily than esters of methoxy-or ethoxy-substituted naphthylethanol. The introduction of a methoxy- or ethoxy-group in the naphthyl radical reinforces the alkyl–oxygen heterolysis, especially when at position 2 and ethoxyl is more effective than methoxyl. It is suggested that this is due to steric factors.

The alkyl–oxygen fission is less strongly promoted by electron-release when the substituent is at position 6. We infer that when these alkoxy-groups are in the other ring the conjugative electron-release is inefficiently relayed to the alkyl carbon atom.