Ruthenium Oxidase Catalysis for Site-Selective C-H Alkenylations with Ambient O2 as the Sole Oxidant.

Ruthenium(II) oxidase catalysis by direct dioxygen-coupled turnover enabled step-economical oxidative C-H alkenylation reactions at ambient pressure. Versatile ruthenium(II) biscarboxylate catalysts displayed ample substrate scope and proved applicable to weakly coordinating and removable directing groups. The twofold C-H functionalization strategy was characterized by exceedingly mild reaction conditions as well as excellent positional selectivity.

Ruthenium(II)-catalyzed C-H activation/alkyne annulation by weak coordination with O2 as the sole oxidant.

Aerobic oxidative CH functionalizations of weakly coordinating benzoic acids have been accomplished with versatile ruthenium(II) biscarboxylates under ambient oxygen or air. Mechanistic studies identified the key factors controlling the elementary step of the oxidation of the ruthenium(0) complex.

Ruthenium-catalyzed oxidative C-H alkenylation of aryl carbamates.

A cationic ruthenium(II) catalyst enabled highly efficient oxidative alkenylations of electron-rich arenes bearing removable, weakly coordinating carbamates, and allowed for cross-dehydrogenative C-H bond functionalization in an aerobic manner.

Cationic ruthenium catalysts for alkyne annulations with oximes by C-H/N-O functionalizations.

Cationic ruthenium(II) complexes enabled efficient redox-neutral annulations of alkynes with readily available oximes. The catalytic dehydrative C-H/N-O bond functionalization proved to be broadly applicable and was shown to proceed through a reversible cyclometalation.

Palladium-catalyzed direct C-H bond alkynylations of heteroarenes using gem-dichloroalkenes.

Palladium-catalyzed direct alkynylations of heteroarenes were accomplished with inexpensive gem-dichloroalkenes as user-friendly electrophiles, which set the stage for a modular, step-economical synthesis of diversely decorated heteroaryl alkynes with ample scope.

C-H bond arylations and benzylations on oxazol(in)es with a palladium catalyst of a secondary phosphine oxide.

An air-stable, well-defined palladium complex derived from secondary phosphine oxide (SPO) (1-Ad)(2)P(O)H enabled efficient C-H bond functionalizations with ample scope, which set the stage for direct arylations and benzylations of (benz)oxazoles, as well as unprecedented palladium-catalyzed C-H bond arylations on nonaromatic oxazolines.

Well-defined air-stable palladium HASPO complexes for efficient Kumada-Corriu cross-couplings of (hetero)aryl or alkenyl tosylates.

Palladium complexes of representative heteroatom-substituted secondary phosphine oxide (HASPO) preligands were synthesized and fully characterized, including X-ray crystal structure analysis. Importantly, these well-defined complexes served as highly efficient catalysts for Kumada-Corriu cross-coupling reactions of aryl, alkenyl, and even heteroaryl tosylates. Particularly, an air-stable catalyst derived from inexpensive PinP(O)H displayed a remarkably high catalytic efficacy, which resulted in cross-couplings at low catalyst loadings under exceedingly mild reaction conditions with ample scope.