Aryldifluoroboranes: Lewis acidity and catalytic activity in the alkylation of phenols

Abstract

A series of aryldifluoroboranes was tested as homogeneous catalysts. The Lewis acidity of different ArBF2 was determined by the Gutmann-Beckett method. A simple linear correlation was found between the Lewis acidity of ArBF2 and the rate of phenol alkylation with styrene. Unexpected acceleration of alkylation of 4-XC6H4OH was observed in the series of X = OMe < tert-Bu < H