Palladium-Catalyzed Conjugate Addition of Organosiloxanes to α,β-Unsaturated Carbonyl Compounds and Nitroalkenes

The addition of aryltrialkoxysilanes to alpha,beta-unsaturated carbonyl compounds (ketones, aldehydes) and nitroalkenes in the presence of SbCl(3), TBAF, AcOH, and a catalytic amount of Pd(OAc)(2), in CH(3)CN at 60 degrees C, provides the corresponding conjugate addition products in moderate to good yields. The addition of equimolar amounts of SbCl(3) and TBAF is necessary for this reaction to proceed smoothly. The arylpalladium complex, which is generated by the transmetalation from a putative hypercoordinate silicon compound, is considered to be the catalytically active species.