Mono-Oxidation of Bidentate Bis-phosphines in Catalyst Activation: Kinetic and Mechanistic Studies of a Pd/Xantphos-Catalyzed C-H Functionalization

被引：100

作者：

Ji, Yining ^{[1
]}

Plata, R. Erik ^{[1
]}

Regens, Christopher S. ^{[2
]}

Hay, Michael ^{[2
]}

Schmidt, Michael ^{[2
]}

Razler, Thomas ^{[2
]}

Qiu, Yuping ^{[2
]}

Geng, Peng ^{[2
]}

Hsiao, Yi ^{[2
]}

Rosner, Thorsten ^{[2
]}

Eastgate, Martin D. ^{[2
]}

Blackmond, Donna G. ^{[1
]}

机构：

[1] Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA

[2] Bristol Myers Squibb, Chem Dev, New Brunswick, NJ 08903 USA

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 2015年 / 137卷 / 41期

基金：

美国国家科学基金会;

关键词：

METALATION-DEPROTONATION MECHANISM; PROTON-ABSTRACTION MECHANISM; COMPACT EFFECTIVE POTENTIALS; EXPONENT BASIS-SETS; DIRECT ARYLATION; INTRAMOLECULAR ARYLATION; ZEROVALENT PALLADIUM; BOND ACTIVATION; OXIDE LIGANDS; HECK REACTION;

D O I：

10.1021/jacs.5b01913

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Kinetic, spectroscopic, crystallographic, and computational studies probing a Pd-catalyzed C-H arylation reaction reveal that mono-oxidation of the bis-phosphine ligand is critical for the formation of the active catalyst. The bisphosphine mono-oxide is shown to be a hemilabile,bidentate ligand for palladium. Isolation of the oxidative addition adduct, with structural elucidation by X-ray analysis, showed that the mono-oxide was catalytically competent, giving the same reaction rate in the productive reaction as the Pd(II)/xantphos precursor. A dual role for the carboxylate base in both catalyst activation and reaction turnover was demonstrated, along with the inhibiting effect of excess phosphine ligand. The generality of the role of phosphine mono-oxide complexes in Pd-catalyzed coupling processes is discussed.

引用

页码：13272 / 13281

页数：10

共 88 条

[1] Assisted ruthenium-catalyzed C-H bond activation: Carboxylic acids as cocatalysts for generally applicable direct arylations in apolar solvents [J].