Dialkyl and diaryl boron halides: reductive opening of benzylidene acetals

Dimethylboron bromide or diphenylboron bromide can be used in combination with borane to achieve the regiocontrolled conversion of benzylidene acetals to their corresponding hydroxy benzyl ethers with moderate to high yields. Keywords: dimethylboron bromide, diphenylboron bromide, reductive opening, benzylidene, acetals.