Chemoselective Deoxygenation of 2° Benzylic Alcohols through a Sequence of Formylation and B(C6F5)3-Catalyzed Reduction

A sequence of formylation and B(C6F5)(3)-catalyzed reduction of the resulting formate with Et3SiH enables the chemoselective deoxygenation of secondary benzylic alcohols. Primary benzylic and tertiary non-benzylic alcohols are not reduced by this protocol. The formyl group fulfills a double role as activator and self-sacrificing protecting group. The deoxygenation of these formates is fast and can be carried out in the presence of other potentially reducible groups. Neighboring-group participation was found in the deoxygenation of certain diol motifs.

Automated summary

The chemoselective deoxygenation of secondary benzylic alcohols can be achieved through a series of formylation and reduction reactions, forming formates. In this process, the formyl group acts as both an activator and a self-sacrificing protecting group, allowing the reaction to proceed in the presence of other reducible groups.