Liebeskind-Srogl C----C Cross-Coupling Reaction

New kid on the block: The cross-coupling of thioorganic compounds with boronic acids under neutral conditions in the presence of catalytic palladium(0) and a stoichiometric amount of a copper(I) oxygenate has emerged as a very useful method for the construction of C---C bonds (see scheme). This intriguing and mechanistically unprecedented base-free coupling has distinct advantages, in particular when traditional Pd⁰-catalyzed cross-coupling is not possible.Although a plethora of highly selective and reliable methods for the construction of C---C bonds are known to organic chemists, there is growing interest in the development of new protocols that offer different or orthogonal reactivity to that of existing methods. In 2000, Liebeskind and Srogl described a mechanistically unprecedented transition-metal-catalyzed cross-coupling of thioesters with boronic acids to produce ketones under neutral conditions. This desulfitative cross-coupling process is catalytic in palladium(0), stoichiometric in copper(I), and applicable to a range of organosulfur derivatives and nucleophilic organometallic reagents. In this Minireview, we highlight recent applications of this intriguing cross-coupling reaction in modern organic synthesis, with an emphasis on cases in which traditional methods for C---C bond formation have failed.