Abstract
The mechanism and stereochemistry of the reaction between hydrogen peroxide and alcohols or alkyl hydrogen phthalates have been investigated by means of optically active reagents. Indications from the work of Foster and White that these reactions proceed by an SN1-like mechanism with inversion of configuration accompanied by racemisation have been largely confirmed. It has been found that in some cases a previously undetected SNi component may exist, the reaction proceeding with partial retention of configuration. It is probable that both types of mechanism occur simultaneously, the residual asymmetry in the produce, which varies between +G and -G of that of the starting material, resulting from a balance between the SN1 mechanism, giving partial inversion, and the SNi mechanism, giving partial retention of configuration. The small change in the contribution of the two mechanisms required to bring about the change in stereochemical result, may be due to a slight variation in the alkyl group of the alcohol or ester (e.g. 1-phenylpropanol gives inversion, and l-phenylbutanol retention of configuration), or, as all the reactions involving alcohols were heterogeneous, to a slight change in the mutual solubility of alcohol and hydrogen peroxide. Several new methods for the reduction of peroxides have been investigated, and some general conclusions can be drawn regarding the mechanism of such reductions. As an outcome of this work it has been found that some ethers are very reactive towards hydrogen peroxide and hydroperoxides, to give the corresponding hydroperoxides and dialkyl peroxides, Optically active ethyl l-phenyl-ethyl ether yields l-phenylethyl hydroperoxide with partial inversion of configuration: the reaction therefore probably proceeds by the SN1 mechanism. In the second part of the thesis the stereochemistry of benzoyl peroxide and tert-butyl diperterephalate have been investigated by the method of dip le moments. Both substances have been found to have finite dipole moments, equal to 1.52 D and 3.71 D respectively.