DUGi

Catalytic C–S, C–Se, and C–P Cross-Coupling Reactions Mediated by a CuI/CuIII Redox Cycle

http://dugi.udg.edu/item/http:@@@@hdl.handle.net@@10256@@8642

A well-defined macrocyclic aryl-CuIII complex (1) readily reacts with a series of R–SH, Ar–SH, Ar–SeH, and (RO)2(O)–PH (R = alkyl) nucleophiles to quantitatively afford the corresponding aryl alkyl thioethers, biaryl thioethers, biaryl selenide, and aryl dialkyl phosphonates, respectively. Competition experiments using bifunctional substrates revealed the important impact of lower pKa values in order to discriminate between functional groups, although other influencing parameters such as steric effects have been identified. The catalytic version of these reactions is achieved using aryl bromide and aryl chloride model substrates, affording C–S, C–Se, and C–P coupling compounds in excellent to moderate yields. Low-temperature UV–vis and NMR monitoring of the reactions of complex 1 with a variety of nucleophiles support the formation of a ground-state 1–nucleophile adduct. A mechanistic proposal for reaction of 1 with S-nucleophiles involving key nucleophile deprotonation and aryl-nucleophile reductive elimination steps is finally described

We thank Dr. A. Casitas for fruitful discussions. We acknowledge financial support from the European Research Council for Project ERC-2011-StG-277801 to X.R., MICINN of Spain (CTQ2009-08464/BQU to M.C., CT2009-08328 to T.P., and Ph.D. FPI grant to M.F.), Consolider-Ingenio CSD2010-00065, and the Catalan DIUE of the Generalitat de Catalunya (2009SGR637). X.R. and M.C. acknowledge ICREA-Academia awards. We thank STR’s from UdG for technical support

American Chemical Society