Zn; NH4Cl in tetrahydrofuran; water air; addn. of organotin (1 equiv.) to suspension of Zn-powder (1-2 equivs.) in satd. soln. of NH4Cl in H2O:THF, dropwise addn. of benzyl bromide(1-2 equivs.) with rate maintaining gentle reflux, stirring with coolin g to room temp. for 30 min;