Functionalised fluoroalkenes, which are attractive molecules owing to their biological activity,l.2 are generally obtained in multi-step sequences.G5 The addition of HF to activated -GC- bonds should make similar compounds more acces- sible. However neither anhydrous HF,6 except when treated with CF3GCH,7 nor amine-HF complexes investigated by Olahs and Yonedag bring about this addition. The H2F3- ion, in which the H . - - F hydrogen bonds ...
