Oxidative palladium(II) catalysis: A highly efficient and chemoselective cross-coupling method for carbon-carbon bond formation under base-free and nitrogenous-ligand conditions.
We report herein the development of a general and mild protocol of oxygen-promoted Pd(II) catalysis resulting in the selective cross-couplings of alkenyl- and arylboron compounds with various olefins. Unlike most cross-coupling reactions, this new methodology works well even in the absence of bases, consequently averting undesired homo-couplings. Nitrogen-based ligands including dimethyl-phenanathroline enhance reactivities and offer a highly efficient and stereoselective methodology to overcome challenging substrate limitations. For instance, oxidative palladium(II) catalysis is effective with highly substituted alkenes and cyclic alkenes, which are known to be incompatible with other known catalytic conditions. Most examined reactions progressed smoothly to completion at low temperatures and in short times. These interesting results provide mechanistic insights and utilities for a new paradigm of palladium catalytic cycles without bases.
Yoo
Kyung Soo
KS
Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, USA.
Yoon
Cheol Hwan
CH
Mishra
Rajesh K
RK
Jung
Young Chun
YC
Yi
Sung Wook
SW
Jung
Kyung Woon
KW
D000475:Alkenes / Q000737:chemistry; D001895:Boron / Q000737:chemistry; D001897:Boronic Acids / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003512:Cyclohexanones / Q000737:chemistry; D004951:Esterification; D008024:Ligands; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D012997:Solvents; D013696:Temperature
D000475:Alkenes; D001897:Boronic Acids; D003432:Cross-Linking Reagents; D003512:Cyclohexanones; D008024:Ligands; D012997:Solvents; C036468:cyclohexanone; D010165:Palladium; D002244:Carbon; D009584:Nitrogen; D001895:Boron