Polyfluoroorganotrifluoroborates and -difluoroboranes: interesting materials in fluoroorgano and fluoroorgano-element chemistry

The aimed introduction of the polyfluoroorgano groups (4-C5F4N), C6F13C2H4, and C2F5 into methoxy group-containing boron electrophiles is reported. The new compounds obtained after transformations K[(4-C5F4N)BF3], (4-C5F4N)BF2, K[C6F13C2H4BF3], C6F13C2H4BF2, K[(C2F5)(2)B(OMe)(2)], and K[(C2F5)(2)BF2] were isolated and characterised. Additionally some of their precursors as there are Li(4-C5F4N), Li[(4-C5F4N)B(OMe)(3)], (4-C5F4N)B(OH)(2) and the by-products Li[(4-C5F4N)(2)B(OMe)(2)], (4-C5F4NOOH, and K[(4-C5F4N)(2)BF2] are described. The usefulness of polyfluoroorganodifluoroboranes for introducing polyfluoroorgano groups into hypervalent FE-F bonds is demonstrated by the synthesis of [C6F5(4-C5F4N)I][BF4] and [p-FC6H4(trans-CF3CF=CF)I][BF4]. (C) 2004 Elsevier B.V. All rights reserved.