Chemical and stereochemical behaviour of bifunctional enantiomeric silicon compounds : I. Study of α-naphthylferrocenyl-fluorosilane and -chlorofluorosilane

The synthesis of the first bifunctional enantiomeric silicon compounds is described. A high selectivity between the two functional groups is observed in substitution reactions with organolithium compounds and Grignard reagents, the more polarizable group being specifically replaced. The stereochemistry of the reactions has been determined by chemical correlations. The stability of the pentacoordinated intermediate (discussed in terms of apicophilicity of the various groups) does not suffice to explain the results. Inversion of the configuration comes from an axial attack of the reactant and retention of configuration is explained by an equatorial attack.