Radical reactions using decacarbonyldimanganese under biphasic conditions

Radical reactions of alkyl halides, initiated by photolysis in the presence of decacarbonyldimanganese, can be performed in biphasic media. Reactions in the presence of aqueous sodium hydroxide together with a phase-transfer catalyst result in the efficient removal of manganese halide by-products and also lead to the regeneration of decacarbonyldimanganese. A range of efficient radical couplings, cyclisations and intermolecular addition reactions were performed under these conditions. This included the development of a new tandem radical addition-ionic cyclisation sequence that was employed in a short approach to (±)-coronamic acid.