CH Bond Functionalization in Water Catalyzed by Carboxylato Ruthenium(II) Systems

Ruthenium-catalyzed direct C-3 oxidative olefination of imidazo[1,2-a]pyridines

Ruthenium-catalyzed regioselective C-3 oxidative olefination of imidazo[1,2-a]pyridines.

Ruthenium-catalyzed highly regio- and stereoselective hydroarylation of aromatic sulfoxides with alkynes via C–H bond activation

A ruthenium-catalyzed hydroarylation of aromatic sulfoxides with alkynes in the presence of AgSbF₆ and pivalic acid yielding trisubstituted alkenes is described.

K-bis(2-ethylhexyl) phosphate (BEHPK): a novel additive for C–H arylation

Use of K-bis(2-ethylhexyl) phosphate (BEHPK) as an additive enabled highly reproducible Ru-catalyzed C–H arylation under low catalyst loading (0.5 mol%).

C(sp3)-H bond arylations catalyzed by well-defined [Ru(O2CMes)2(p-cymene)]

The well-characterized ruthenium(II) biscarboxylate complex [Ru(O2CMes)2(p-cymene)] enabled versatile direct (hetero)arylations of C(sp(3))-H bonds with low (co)catalyst loading and ample substrate scope. Detailed mechanistic studies provided strong support for a facile and reversible C(sp(3))-H bond metalation.

Solvent-free palladium-catalyzed direct arylation of heteroaromatics with aryl bromides

Solvent is one of the major sources of waste in the course of catalyzed direct arylations. Some palladium-catalyzed direct arylations of heteroaromatics can be advantageously performed without any solvent. In the presence of palladium catalysts (1 mol %) and potassium acetate as the base, the direct 5-arylation of some thiazoles, thiophenes, furans, or pyrroles with aryl bromides as coupling partners proceeds highly regioselectively and in moderate to high yields. However, the use of these solvent-free conditions is limited to electron-deficient aryl bromides.

Ruthenium-catalyzed C-H bond arylations of arenes bearing removable directing groups via six-membered ruthenacycles

Ruthenium-catalyzed direct arylations of phenols bearing removable directing groups were accomplished through carboxylate assistance via six-membered ruthenacycles as key intermediates.

Versatile synthesis of isocoumarins and α-pyrones by ruthenium-catalyzed oxidative C-H/O-H bond cleavages

An inexpensive cationic ruthenium(II) catalyst enabled the expedient synthesis of isocoumarins through oxidative annulations of alkynes by benzoic acids. This C-H/O-H bond functionalization process also proved applicable to the preparation of α-pyrones and was shown to proceed by rate-limiting C-H bond ruthenation.

Synthesis of angiotensin II receptor blockers by means of a catalytic system for C-H activation

A highly efficient catalytic system for C-H activation has been worked out that involves inexpensive RuCl(3)·xH(2)O and a specific amount of PPh(3). This procedure has been successfully applied to a practical synthesis of angiotensin II receptor blockers (ARBs). The residual ruthenium that existed in the reaction mixture was thoroughly removed by treatment with properly selected metal scavengers. The new process permits ready access to the important class of drugs in a highly atom-economical and sustainable manner.