Regio-and Stereoselective Allylic Coupling Reactions of Allyltrifluorosilanes

Abstract

Regio-and stereoselective cross-coupling reactions using allyltrifluorosilanes are reviewed. γ-Selective allylation of organic halides or triflates with allyltrifluorosilanes takes place in the presence of a fluoride salt and Pd (PPh₃)₄ as a catalyst, giving the corresponding allylic compounds in good yields. The regioselectivity of this reaction is strongly influenced by a palladium catalyst ; high α-selectivity was observed in reactions catalyzed by PdCl₂ [Ph₂P (CH₂)_nPPh₂](n=2 or 3). Optically active allylsilanes undergo the γ-selective allylation of aryl triflates to give optically active allylic arenes. The absolute configuration of the allylic arenes could be controlled by choosing a fluoride salt. Allylation of quinones with allyltrifluorosilanes takes place with high regioselectivity in the presence of FeCl₃·6H₂O. This method was used to synthesize biologically active isoprenoid quinones such as plastoquinone-1 and vitamin K₁.