Alkyl Halide Reduction and Stereochemical Effects

A type of reaction of considerable mechanistic interest in the kinetics of electrochemical and solvolytic reactions is the reduction of alkyl halides RX where a nucleophilic substitution type of reaction occurs with the electrode acting as the nucleophile. The anion X and the hydrocarbon RH are the main products. In some cases, organometallic intermediates are produced, e.g., in the reduction of alkyl iodides or bromides at Pb. Here the process which leads to lead tetraalkyls is of considerable commercial significance. 

Stereochemical studies have been carried out by Annino et on 

Although preliminary experiments of Annino et with optically 

The observed stereochemistry (Table 5) may be explained by means of two main proposals (i) that the initial attack by the electrode occurs on the same side of the molecule as the Br atom to give an adsorbed complex with the same configuration as the reactant (ii) the overall stereochemistry is then determined by a stereoselective reaction of the free or electrode- 

Reduction of 1-Bromo-2,2-diphenylcyclopropanecarboxylic Acid (la), Methyl 1-Bromo-2,2-diphenylcy-clopropanecarboxalate (lb), and 1-Bromo-1-methyl-2,2-diphenylcyclopropane ( c)  

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