Electrophilic rf Complexes

2) loss of metal (silica coiumn then short path distiiiation) 

The classic rf cyclohexadienyl complexes of Fe(CO)3 first investigated by Fischer and Fischer [56], and subsequently by many research groups (including my own) provide a wealth of examples of studies of regiodirecting effects of substituents. With simple alkyl groups, steric effects send the nucleophile to the co position 

Alkynes at C-1 of a cydohexadienyliron(l-t) complex have also been examined, and found to direct nucleophiles w, but with some a addition (see Section 14.3.8) [6]. Despite its charge-stabilizing capabilities, a C-1 PhS group directs to. Similarly, trimethylsilyl groups at either C-1 or C-2 have been found to direct w, despite the cation-stabilizing properties of SiMcj [130-132]. In the acyclic series, this effect is 

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