Catalytic Asymmetric Hiyama Cross-Couplings of Racemic α-Bromo Esters
作者:Xing Dai、Neil A. Strotman、Gregory C. Fu
DOI:10.1021/ja8009428
日期:2008.3.1
The first catalyticasymmetriccross-coupling of α-halo carbonyl compounds with aryl metal reagents has been developed, thereby generating synthetically useful α-aryl carboxylic acid derivatives in good enantiomeric excess. The method can also be applied to enantioselective alkenylation reactions.
Versatile direct Hiyama‐type C−H arylations of benzamides were accomplished with organosiloxanes by chelation‐assisted cobaltcatalysis. The C−H arylation featured broad substrate scope, including challenging C(sp3)−H activation, the use of γ‐valerolactone as biomass‐derived solvent, and selectively provided the desired biaryls, even when being highly sterically hindered.
We describe herein a regioselective palladium(II)-catalyzedintermolecularhydroarylation of unactivated aliphatic alkenes with electronically and sterically diverse (hetero)arylsilanes under redox-neutral conditions. A removable bidentate 8-aminoquinoline auxiliary was readily employed to dictate the regioselectivity, prevent β-hydride elimination, and facilitate protodepalladation. This silicon-based
Pd(OAc)<sub>2</sub>/DABCO as an Inexpensive and Efficient Catalytic System for Hiyama Cross-Coupling Reactions of Aryl Halides with Aryltrimethoxysilanes
Pd(OAC) 2 /DABCO was found to be an inexpensive and efficient catalyst system for Hiyama cross-coupling reactions of arylhalides with aryltrimethoxysilanes. In the presence of Pd(OAc) 2 , DABCO, and TBAF, coupling of a number of arylhalides with aryltrimethoxysilanes underwent efficiently to afford the corresponding cross-coupled products in moderate to excellent yields.
Ruthenium(<scp>ii</scp>)-catalyzed ortho-C–H arylation of diverse N-heterocycles with aryl silanes by exploiting solvent-controlled N-coordination
作者:Pradeep Nareddy、Frank Jordan、Michal Szostak
DOI:10.1039/c7ob00818j
日期:——
We report the first method for the direct, regioselectiveRu(II)-catalyzed oxidative arylation of C–H bonds in diverse N-heterocycles with aryl silanes by exploiting solvent-controlled N-coordination. The reaction takes advantage of the attractive features of organosilanes as coupling partners, providing proof of concept for N-directed Ru(II)-catalyzed C–H arylation. This novel, operationally-simple