Quantitative kinetic investigation on transmetalation of ArZnX in a Pd-catalysed oxidative coupling.
نویسندگان
چکیده
Transmetalation is the rate-limiting step. [R-Pd-Ar] was suggested to be the resting species from the kinetic studies. Quantitative measurement of the transmetalation of ArZnCl with [R-Pd-Ar] from a live Pd-catalysed oxidative coupling reaction was conducted and the corresponding activation enthalpy was determined as 12.3 kcal mol(-1).
منابع مشابه
Pd-Catalyzed Aerobic Oxidative Coupling of Arenes: Evidence for Transmetalation between Two Pd(II)-Aryl Intermediates
Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C-H activation of two arenes to afford a Pd(II)ArAr' intermediate, which then undergoes C-C reductive elimination. The key Pd(II)ArAr' intermediate could form via a "monometallic" pathway involving sequential C-H activation at a single Pd(II) center, or via a "bimetallic...
متن کاملWhich one is faster? A kinetic investigation of Pd and Ni catalyzed Negishi-type oxidative coupling reactions.
The difference between Pd and Ni has been investigated based on the Negishi-type oxidative coupling reactions in which reductive elimination was proved to be the rate determining step. Although DFT calculations illustrate that the Pd catalyzed reaction should be faster than the Ni catalyzed reaction under these conditions, kinetic experiments indicate that the reaction rate of Pd and Ni is depe...
متن کاملMechanistic Significance of the Si–O–Pd Bond in the Palladium-Catalyzed Cross-Coupling Reactions of Arylsilanolates
Through the combination of reaction kinetics (both stoichiometric and catalytic), solution- and solid-state characterization of arylpalladium(II) arylsilanolates, and computational analysis, the intermediacy of covalent adducts containing Si-O-Pd linkages in the cross-coupling reactions of arylsilanolates has been unambiguously established. Two mechanistically distinct pathways have been demons...
متن کاملMechanistic Significance of the Si–O–Pd Bond in the Palladium-Catalyzed Cross-Coupling Reactions of Alkenylsilanolates
Through the combination of reaction kinetics (both catalytic and stoichiometric) and solid-state characterization of arylpalladium(II) alkenylsilanolate complexes, the intermediacy of covalent adducts containing Si-O-Pd linkages in the cross-coupling reactions of organosilanolates has been unambiguously established. Two mechanistically distinct pathways have been demonstrated: (1) transmetalati...
متن کاملRegioselective oxidative Pd-catalysed coupling of alkylboronic acids with pyridin-2-yl-substituted heterocycles.
A total of 19 alkylated heterocycles (thiophenes, benzothiophenes, pyrroles, furans) were prepared (36-99% yield) from the respective pyridin-2-yl-substituted precursors employing alkylboronic acids as the C-H alkylating reagents in an oxidative (Ag2CO3 and 2,6-dimethyl-1,4-benzoquinone as oxidants) Pd-catalysed coupling reaction.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Chemical communications
دوره 49 83 شماره
صفحات -
تاریخ انتشار 2013