Control of Homocoupling Versus Reduction in Titanium(III)-Mediated Radical Opening of Styrene Oxides

We describe the use of titanocene monochloride in the implementation of an experimental procedure that enables control of the homolytic opening of styrene oxides in a chemoselectively controlled manner. This leads either to homocoupling products or to phenethyl alcohol derivatives. The process occurs via the generation of benzyl radicals, which may undergo a) recombination or b) reduction, yielding benzyl-Ti(IV) species upon subsequent addition of H2O to the corresponding hydroxylated compounds. The main goal of this work is the study of the reactivity pattern of styrene oxides towards the formation of the mentioned products, thereby adding value to this interesting building block.