B(C 6 F 5 ) 3 -Catalyzed, Metal-Free Reduction of Diselenides and Ditellurides, and One-Pot Syntheses of O,Se -Acetals, Selenoesters, Selanylketones, and Telluroesters

Silyl selenides and tellurides were successfully synthesized by respectively reacting diselenides or ditellurides with silanes under catalysis of B(C6F5)3 at rt. Without workup, these were reacted with a variety of aldehydes, carboxylic acid derivatives, and α,β-unsaturated ketones under nucleophilic catalysis generating O,Se-acetals, seleno- and telluroesters, and selanylketones in good to excellent yields, respectively. A triethylsilyl O,Se-acetal was utilized in a three-component radical reaction.