Selective Reduction of Carboxylic Acids to Aldehydes Catalyzed by B(C 6 F 5 ) 3

B(C(6)F(5))(3) efficiently catalyzes hydrosilylation of aliphatic and aromatic carboxylic acids to produce disilyl acetals under mild conditions. Catalyst loadings can be as low as 0.05 mol %, and bulky tertiary silanes are favored to give selectively the acetals. Acidic workup of the disilyl acetals results in the formation of aldehydes in good to excellent yields.