Ni(II)/Al(0) mediated benzylic $$\hbox {Csp}^{3}$$-$$\hbox {Csp}^{3}$$ coupling in aqueous media

The reaction of benzyl bromides and chlorides with aluminium metal powder or foil (1.2 eqv.) in the presence of catalytic nickel nitrate (10 mol%) in water at room temperature resulted in homocoupling to the corresponding bibenzyl products which were isolated in moderate to good yields. In sharp contrast, the same reaction in organic solvents like dichloromethane, dimethylformamide, acetonitrile, methanol and toluene yielded only a trace amount...