B(C6 F5 )3 -Catalyzed Chemoselective Defunctionalization of Ether-Containing Primary Alkyl Tosylates with Hydrosilanes.

Catalytic C(sp3 )-O bond cleavage promoted by B(C6 F5 )3  /Et3 SiH proceeds preferentially with primary tosylates in the presence of primary and secondary silyl ethers and aryl ethers. This reactivity difference enables the chemoselective defunctionalization of several 1,n-diols, and the efficiency of the new procedure is highlighted by the selective deoxygenation of the hydroxymethyl group of an orthogonally protected carbohydrate. Tosylates with an adjacent phenyl group are cleaved with anchimeric assistance.