The C-H activated controlled mono- and di-olefination of arenes in ionic liquids at room temperature

Ruthenium (II) Catalyzed C(sp2 )-H Bond Alkenylation of 2-Arylbenzo[d]oxazole and 2-Arylbenzo[d]thiazole with Unactivated Olefins

Functionalization of the bio-relevant heterocycles 2-arylbenzo[d]oxazole and 2-arylbenzo[d]thiazole has been achieved through Ru(II)-catalyzed alkenylation with unactivated olefins leading to selective formation of the mono-alkenylated products. This approach has a broad substrate scope with respect to the coupling partners, affords high yields, and works for gram scale synthesis using a readily available Ru-based catalyst. Mechanistic studies reveal a C-H activation pathway for the dehydrogenative coupling leading to the alkenylation. However, the results of the ESI-MS-guided deuterium kinetic isotope effect studies indicate that the C-H activation stage may not be the rate-determining step of the reaction. The use of a radical scavenging agent such as TEMPO did not show any detrimental effect on the reaction outcome, eliminating the possibility of the involvement of a free-radical pathway.

Ruthenium(II)-Catalyzed α-Fluoroalkenylation of Oxime Ethers with gem-Difluorostyrenes via C-H Activation and C-F Cleavage

A novel route for ruthenium(II)-catalyzed α-fluoroalkenylation of oxime ethers with gem-difluorostyrenes via C-H activation and C-F cleavage has been developed for the first time. Notably, the alkenyl units of products exhibit exclusive Z-configuration. This reaction features a broad substrate scope and good functional group tolerance. A plausible reaction mechanism is confirmed by an available cycloruthenated intermediate. Besides, the O-methyl oximyl-directing group can be readily removed to access the α-fluoroalkenylated acetophenones.