| Summary: | We report an innovative approach for the selective synthesis of polyfunctional derivatives by cross-combination of different radicals generated under mild conditions. The coordinating effect of Ti(IV) plays a key role in the reaction mechanism: due to its chelating action on the hydroxyl groups, it promotes the homolytic C-C bond cleavage of α,β-dihydroxy ketones by enhancing the captodative effect and the consequent stabilization of the corresponding α-hydroxy-α-carbonyl radicals. When these radicals are generated in the presence of stoichiometric amounts of TiCl and 2,2′-azo-bis-isobutyronitrile (AIBN) is employed as a source of α-cyanoisopropyl radicals, the selective radical-radical cross-coupling is observed, affording the corresponding β-hydroxynitriles in high yields. This innovative methodology allows application of the well-known Ingold-Fischer effect to a wider range of stabilized carbon-centered radicals, whose formation derives from the chelating action of Ti(IV).
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