Alternative method for alkylation of arylpolyhalomethanes with trialkylborane in the presence of magnesium

Reduction of benzal halide derivatives and α,α,α,-trichloromethylbenzene by magnesium powder in DMAc affords α-halocarbanions which then react with triethylborane to give alkylated products. After oxidation with H2O2–NaOH, secondary or tertiary alcohols are obtained. Under the same conditions, 1,1-diphenylpropane is obtained from α,α-dichlorodiphenylmethane.