Catalytic C−H/Olefin Coupling

Abstract

The cleavage and addition of ortho C-H bonds in various aromatic compounds such as ketones, esters, imines, imidates, nitrile, and aldehydes to olefins and acetlylenes can be achieved catalytically with the aid of ruthenium catalysts. The reaction is generally highly efficient and useful in synthetic methods. The coordination to the metal center by a heteroatom in directing groups such as carbonyl and imino groups is the key. The reductive elimination to form a C-C bond is the rate-determining step.

Palladium-Catalyzed Benzene Arylation: Incorporation of Catalytic Pivalic Acid as a Proton Shuttle and a Key Element in Catalyst Design

“…In this context, direct arylation, which substitutes one of the activated arenes (usually the organometallic) with an unfunctionalized arene, has attracted significant attention. 2 First reported nearly 20 years ago with electron-rich arenes such as indole, 3 the scope of these transformations has recently undergone rapid expansion. Despite important advances, the need for directing groups 4 or nucleophilic, electron-rich substrates 5 is only beginning to be addressed.…”

グリーン有機分子変換プロセスを指向したセリア担持ルテニウム触媒の開発

“…The Ru/CeO2 catalyst could be used in the reaction with methyl, trifluoromethyl, and fluoro-substituted chlorobenzenes. However, the reaction of 16a and chlorobenzenes bearing coordinating substituents such as methoxy, cyano, or acyl groups did not proceed at all, probably because of the coordination of low-valent ruthenium species on these functional groups 70) , which might hamper direct arylation. This limitation can be overcome by the addition of a small amount of PPh3: the reaction of 16a with 4-chloroanisole (17b) in the presence of Ru/CeO2 (2.5 mol%) and PPh3 (5 mol%) at 170 for 24 h gave 10-(4-methoxyphenyl)benzo[h] quinoline (18ab) in 70 % yield.…”

Rh(III)-Catalyzed, Highly Selectively Direct C–H Alkylation of Indoles with Diazo Compounds

“…Therefore, direct functionalization of indoles has attracted much attention from synthetic chemists. With the development of transition-metal-catalyzed C-H bond activation, it has become the most straightforward approach for functionalization of indoles in a step-and atom-economical fashion [5][6][7][8][9][10][11][12]. Nevertheless, compared with C3-H functionalization, the methods that allow for the C2-H functionalization of indoles are still rare due to the weak reactivity of the C-H bond at the C2-position of an indole [13,14].…”