有機ケイ素化合物/F^〓/Pd触媒による高選択的交差カップリング反応

抄録

Highly selective cross-coupling reaction of organosilanes with organic halides and organic triflates promoted by palladium catalyst and fluoride ion is described. Organosilicon compounds like (E) - or (Z) -alkenyl, alkynyl, allyl, and arylsilanes smoothly react with alkenyl, allyl and aryl halides to give coupled products with high chemoselectivity and stereospecificity. Under similar conditions, silylation of alkenyl iodides by hexa-methyldisilane and methylation of aryl iodides by (Et₂N)₃S⁺Me₃SiF₂^- take place. The one-pot double cross-coupling of trimethylstannyl (trimethylsilyl) acetylene with two alkenyl iodides is achieved to afford isomerically pure dienynes. The cross-coupling of chiral 1-phenyl-1-trifluorosilylethane with aryl triflates occurrs stereo-specifically, providing optically active coupled products. The stereochemistry of the products is influenced decisively by reaction temperature and solvent used. A transition state model for the transmetallation step in catalytic cycle is proposed on the basis of substituent effect and stereochemical study of this reaction.