Of benzylidene acetals, to form

Selective reduction of benzylidene acetals to form mono-benzyl protected diols was discussed in section 2.3.1, Benzyl ethers but differentiation of the oxygen atoms within benzylidene derivatives can also be achieved in the widely used Hanessian procedure. In this process, benzylic bromination, oxonium ion formation, and nucleophilic attack by bromide ion at the (1°-) 6-position leads to the 4-O-benzoyl-6-deoxy-6-bromo derivative. Figure 2.62 [83]. 

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