Triple para -substitution reactions of B(C 6 F 5 ) 3 and [(C 6 F 5 ) 3 PF] + with P(SiMe 3 ) 3 .

para -Substitution reactions on C 6 F 5 rings of Lewis acids have been exploited to achieve triply substituted derivatives. The reaction of B(C 6 F 5 ) 3 with P(SiMe 3 ) 3 ultimately affords the Lewis acid B(C 6 F 4 P(SiMe 3 ) 2 ) 3 1. This species binds Lewis bases affording the adducts LB(C 6 F 4 P(SiMe 3 ) 2 ) 3 (L = MeCN 2, OPEt 3 3, PMe 3 4, PBu 3 5) and reacts with LiMe to give the salt [Li][MeB(C 6 F 4 P(SiMe 3 ) 2 ) 3 ]·3THF 6. It also reacts with H 2 O to give (L)B(C 6 F 4 PH 2 ) 3 (L = H 2 O 7, MeCN 8). In an analogous fashion, [(C 6 F 5 ) 3 PF][B(C 6 F 5 ) 4 ] was converted to [FP(C 6 F 4 P(SiMe 3 ) 2 ) 3 ] [B(C 6 F 5 ) 4 ] 9 and subsequently to [(MeO)P(C 6 F 4 PH 2 ) 3 ][B(C 6 F 5 ) 4 ] 10.