Aryl and heteroaryl substituent effects in reductions and solvolysis reactions

Abstract

Rates of reduction by sodium borohydride of a series of substituted acetophenones and of acetyl-furans, -pyrroles, and -thiophens have been measured. The results fit the Yukawa–Tsuno equation with ρ 2·68, r 0·28. For the heterocyclic systems σ⁺ values are derived from rate constants for solvolysis of the corresponding carbinyl chlorides and σ values from rate constants for hydrolysis of the carboxylic esters.