Photoinitiated oxidative addition of CF3I to gold(I) and facile aryl-CF3 reductive elimination.
Herein we report the mechanism of oxidative addition of CF3I to Au(I), and remarkably fast Caryl-CF3 bond reductive elimination from Au(III) cations. CF3I undergoes a fast, formal oxidative addition to R3PAuR' (R = Cy, R' = 3,5-F2-C6H4, 4-F-C6H4, C6H5, 4-Me-C6H4, 4-MeO-C6H4, Me; R = Ph, R' = 4-F-C6H4, 4-Me-C6H4). When R' = aryl, complexes of the type R3PAu(aryl)(CF3)I can be isolated and characterized. Mechanistic studies suggest that near-ultraviolet light (λmax = 313 nm) photoinitiates a radical chain reaction by exciting CF3I. Complexes supported by PPh3 undergo reversible phosphine dissociation at 110 °C to generate a three-coordinate intermediate that undergoes slow reductive elimination. These processes are quantitative and heavily favor Caryl-I reductive elimination over Caryl-CF3 reductive elimination. Silver-mediated halide abstraction from all complexes of the type R3PAu(aryl)(CF3)I results in quantitative formation of Ar-CF3 in less than 1 min at temperatures as low as -10 °C.
Department of Chemistry, University of California , Berkeley, California 94720, United States.
Matthew S
MS
Winston
William J
WJ
Wolf
F Dean
FD
Toste
D017612:Gold Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D008027:Light; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013696:Temperature
D017612:Gold Compounds