Activation of Alkyl C–F Bonds by B(C6F5)3: Stoichiometric and Catalytic Transformations

The Lewis acid B­(C6F5)3 is shown to activate a series of alkyl fluorides. In stoichiometric reactions, treatment of sterically demanding phosphines with B­(C6F5)3/alkyl fluorides gives phosphonium fluoroborate salts while treatment of B­(C6F5)3/alkyl fluorides with the salts [tBu3PX]­[XB­(C6F5)3] (X = H, PhS) gives the alkane and the salt byproduct [tBu3PX]­[FB­(C6F5)3]. These fluoroalkanes are also catalytically converted to the corresponding alkanes by reaction of the fluoroalkane and Et3SiH using B­(C6F5)3 as the catalyst.