(Fluoroorgano)fluoroboranes and -borates. 12. Reactions of (trifluorovinyl)lithium with chloro-, chloromethoxy-, and (trifluorovinyl)methoxyboranes, a useful route to (trifluorovinyl)fluoroborate salts

Reactions of LiCFdouble bondCF(2) with the boron electrophiles BCl(OMe)(2), BCl2(OMe), BCl3, and CF(2)double bondCFB(OMe)(2) were studied. The nucleophilic addition of LiCFdouble bondCF(2) to BCl(OMe)(2) (2:1) and BCl2(OMe) (3:1) resulted in formation of a mixture of Li[(CF(2)double bondCF)(n)B(OMe)(4-n)] salts, which were converted to K[(CF(2)double bondCF)(n)BF4-n] (n = 1-4) using aqueous K[HF2]. The salt K[(CF(2)double bondCF)(4)B] was prepared from BCl3 and LiCFdouble bondCF(2) (excess) and subsequent treatment with aqueous KF in 76% yield. The salt K[(CF(2)double bondCF)(2)BF2] was synthesized by reacting (trifluorovinyl)dimethoxyborane with LiCFdouble bondCF(2) and subsequent substitution of methoxy by fluorine. K[(CF(2)double bondCF)(3)BF] was obtained by the reaction of (CF(2)double bondCF)(3)B with KF.