Rhodium-Catalyzed Regioselective Olefination Directed by a Carboxylic Group

Carboxylic acids as traceless directing groups for the rhodium(III)-catalyzed decarboxylative C-H arylation of thiophenes

A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of functional groups were tolerated. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which have conventionally been synthesized through lengthy synthetic sequences. An illustrative example is the one-step gram-scale synthesis of a biologically active 3,5-substituted 2-arylthiophene by way of the current method.

Iron-mediated C–H coupling of arenes and unactivated terminal alkenes directed by sulfur

A sulfur-directed Fe(iii)-mediated ortho C–H coupling of arenes with unactivated terminal alkenes gives products of regioselective alkene chloroarylation.

Coupling of carboxylic acids with internal alkynes by supported ruthenium catalysts: direct and selective syntheses of multi-substituted phthalide derivatives

Supported ruthenium catalysts promote coupling of various kinds of aromatic carboxylic acids with internal alkynes, giving the corresponding multi-substituted phthalide derivatives in high yields. The supported Ru catalyst can be recycled at least five times with no loss of activity.

Transition metal-catalyzed C–H bond functionalizations by the use of diverse directing groups

In this review, a summary of transition metal-catalyzed C–H activation by utilizing the functionalities as directing groups is presented.

Orthogonal selectivity with cinnamic acids in 3-substituted benzofuran synthesis through C–H olefination of phenols

A palladium catalyzed intermolecular annulation of cinnamic acids and phenols has been achieved for the selective synthesis of 3-substituted benzofurans.

Iridium-catalyzed oxidative olefination of furans with unactivated alkenes

The oxidative coupling of arenes and alkenes is an attractive strategy for the synthesis of vinylarenes, but reactions with unactivated alkenes have typically occurred in low yield. We report an Ir-catalyzed oxidative coupling of furans with unactivated olefins to generate branched vinylfuran products in high yields and with high selectivities with a second alkene as the hydrogen acceptor. Detailed mechanistic experiments revealed catalyst decomposition pathways that were alleviated by the judicious selection of reaction conditions and application of new ligands.

Rh(III)-catalyzed decarboxylative coupling of acrylic acids with unsaturated oxime esters: carboxylic acids serve as traceless activators

α,β-Unsaturated carboxylic acids undergo Rh(III)-catalyzed decarboxylative coupling with α,β-unsaturated O-pivaloyl oximes to provide substituted pyridines in good yield. The carboxylic acid, which is removed by decarboxylation, serves as a traceless activating group, giving 5-substituted pyridines with very high levels of regioselectivity. Mechanistic studies rule out a picolinic acid intermediate, and an isolable rhodium complex sheds further light on the reaction mechanism.

Cyclometalated [Cp*M(C^X)] (M = Ir, Rh; X = N, C, O, P) complexes

Isolated and well-defined cyclometalated iridium/rhodium complexes that contain a Cp*M–C (M = Ir, Rh) bond stabilised by the intramolecular coordination of neutral donor atoms (N, C, O or P), together with their applications, were summarized.

Phosphoryl-related directing groups in rhodium(III) catalysis: a general strategy to diverse P-containing frameworks

Herein, a rhodium(III)-catalyzed oxidative C-H activation of simple arylphosphonates and phosphonamides with subsequent coupling with alkenes (olefination), internal alkynes (hydroarylation and oxidative cyclization), or simple arenes to give access to diverse P-containing functional frameworks is reported.

Synthesis of Phenanthridinones from N-methoxybenzamides and aryltriethoxysilanes through Rh(III)-catalyzed C-H and N-H bond activation

An efficient method for the one-pot synthesis of substituted phenanthridinone derivatives from N-methoxybenzamides and aryltriethoxysilanes through rhodium-catalyzed dual C-H bond activation and annulation reactions is described. A double-cycle mechanism is proposed to account for this catalytic reaction. In addition, isotope-labeling studies were performed to understand the intimate mechanism of the reaction.