TY - JOUR
T1 - Direct observation of two-electron Ag(I)/Ag(III) redox cycles in coupling catalysis
AU - Font, Marc
AU - Acuña-Parés, Ferran
AU - Parella, Teodor
AU - Serra, Jordi
AU - Luis, Josep M.
AU - Lloret-Fillol, Julio
AU - Costas, Miquel
AU - Ribas, Xavi
PY - 2014/7/11
Y1 - 2014/7/11
N2 - Silver is extensively used in homogeneous catalysis for organic synthesis owing to its Lewis acidity, and as a powerful one-electron oxidant. However, two-electron redox catalytic cycles, which are most common in noble metal organometallic reactivity, have never been considered. Here we show that a Ag(I)/Ag(III) catalytic cycle is operative in model C-O and C-C cross-coupling reactions. An aryl-Ag(III) species is unequivocally identified as an intermediate in the catalytic cycle and we provide direct evidence of aryl halide oxidative addition and C-N, C-O, C-S, C-C and C-halide bond-forming reductive elimination steps at monometallic silver centres. We anticipate our study as the starting point for expanding Ag(I)/Ag(III) redox chemistry into new methodologies for organic synthesis, resembling well-known copper or palladium cross-coupling catalysis. Furthermore, findings described herein provide unique fundamental mechanistic understanding on Ag-catalysed cross-coupling reactions and dismiss the generally accepted conception that silver redox chemistry can only arise from one-electron processes. © 2014 Macmillan Publishers Limited. All rights reserved.
AB - Silver is extensively used in homogeneous catalysis for organic synthesis owing to its Lewis acidity, and as a powerful one-electron oxidant. However, two-electron redox catalytic cycles, which are most common in noble metal organometallic reactivity, have never been considered. Here we show that a Ag(I)/Ag(III) catalytic cycle is operative in model C-O and C-C cross-coupling reactions. An aryl-Ag(III) species is unequivocally identified as an intermediate in the catalytic cycle and we provide direct evidence of aryl halide oxidative addition and C-N, C-O, C-S, C-C and C-halide bond-forming reductive elimination steps at monometallic silver centres. We anticipate our study as the starting point for expanding Ag(I)/Ag(III) redox chemistry into new methodologies for organic synthesis, resembling well-known copper or palladium cross-coupling catalysis. Furthermore, findings described herein provide unique fundamental mechanistic understanding on Ag-catalysed cross-coupling reactions and dismiss the generally accepted conception that silver redox chemistry can only arise from one-electron processes. © 2014 Macmillan Publishers Limited. All rights reserved.
U2 - 10.1038/ncomms5373
DO - 10.1038/ncomms5373
M3 - Article
VL - 5
M1 - 4373
ER -