Ultrafast Pd-catalyzed Cross-Coupling Reactions of (hetero)aryl-bromides with Organolithium Compounds Under “On-Water” Conditions

Despite their enormous synthetic relevance, the use of polar organolithium reagents has been to date restricted to anhydrous conditions, inert atmosphere, and low temperatures to avoid their fast decomposition and control their high reactivity. One of the most momentous challenge in organic synthesis is the replacement of harsh and volatile organic compounds by more environmentally responsible solvents [1]. Building on our recent findings on the use of organometallics in unconventional reaction media (e.g., deep eutectic solvents and water) [2-6], in this communication we first report that a wide range of alkyl-, and aryllithium reagents undergo fast and regioselective cross-coupling reactions with (hetero)aryl bromides in the presence of a Pd catalyst, under “on water” conditions, at room temperature and under air, to afford the expected adducts in up and over 98% yield. The proposed protocol has been optimized so as to minimize the formation of byproducts mainly arising from a lithium-halogen exchange and from a β- hydride elimination reaction. This methodology opens up new vistas in the perspective of the development of a sustainable organometallic chemistry with s-block reagents. [1] J. García-Álvarez; E. Hevia; V. Capriati, Chem. Eur. J. 2018, DOI: 10.1002/chem.201802873. [2] V. Mallardo; R. Rizzi; F. C. Sassone; R. Mansueto; F. M. Perna; A. Salomone; V. Capriati Chem. Commun. 2014, 50, 8655. [3] L. Cicco; S. Sblendorio; R. Mansueto; F. M. Perna; A. Salomone; S. Florio; V. Capriati Chem. Sci. 2016, 7, 1192. [4] G. Dilauro; M. Dell’Aera; P. Vitale; V. Capriati; F. M. Perna Angew. Chem. Int. Ed., 2017, 56, 10200. [5] L. Cicco; M. J. Rodríguez-Álvarez; F. M. Perna; J. García-Álvarez; V. Capriati Green Chem. 2017, 19, 3069. [6] G. Dilauro; S. Mata García; D. Tagarelli; P. Vitale; F. M. Perna; V. Capriati ChemsSusChem 2018, DOI: 10.1002/cssc.201801382.