caa a22 4500 37892303X CHVBK 20180305123610.0 cr unu---uuuuu 161128e20040101xx s 000 0 eng 10.1351/pac200476030565 doi (NATIONALLICENCE)gruyter-10.1351/pac200476030565 Jutand Anny École Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, F-75231,Paris Cédex 5, France Dual role of nucleophiles in palladium-catalyzed Heck, Stille, and Sonogashira reactions [Elektronische Daten] [Anny Jutand] In palladium-catalyzed Heck, Stille, or Sonogashira reactions, the nucleophiles-respectively, alkenes, vinylstannanes, or alkynes-are involved in carbopalladation or transmetallation steps that follow the oxidative addition of an aryl halide or triflate to a Pd0 complex. As soon as the nucleophiles possess a C=C or a C 'triple-bond' C bond capable of coordinating the Pd0 complex active in the oxidative addition, they play a dual role since they interfere in the oxidative addition by a decelerating effect due to a partial coordination of the active Pd0 complex. Indeed, its concentration decreases due to the formation of either unreactive complexes (η2-RCH=CH2)Pd0L2 (R = Ph, CO2Et, L = PPh3 ; R = Bu3Sn, L = AsPh3), (η2-RCH=CH2)Pd0L2(OAc)- (R = Ph, L = PPh3), (η2-R-C 'triple-bond' CH)Pd0L2 (R = Ph, L = PPh3) or more slowly reactive complexes (η2-R-C 'triple-bond' CH)Pd0L2 (R = CO2Et, L = PPh3), (η2-RCH=CH2)Pd0L2 (R= CO2Me, L2 = dppf). Whenever the oxidative addition is faster than the ensuing carbopalladation or transmetallation, the decelerating effect of the nucleophiles in the oxidative addition is in favor of a better efficiency for the catalytic cycle by bringing the rate of the fast oxidative addition closer to that of the slow carbopalladation or transmetallation steps. © 2013 Walter de Gruyter GmbH, Berlin/Boston Pure and Applied Chemistry De Gruyter 76/3(2004-01-01), 565-576 0033-4545 76:3<565 2004 76 pac https://doi.org/10.1351/pac200476030565 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1351/pac200476030565 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Jutand Anny École Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, F-75231,Paris Cédex 5, France NATIONALLICENCE 773 0- Pure and Applied Chemistry De Gruyter 76/3(2004-01-01), 565-576 0033-4545 76:3<565 2004 76 pac CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter