Yongbo Zhou

Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: selective hydrogenation of alkynes with formic acid.

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Brϕnsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.

Copper-Catalyzed Aerobic Oxidative Amination of sp3C–H Bonds: Efficient Synthesis of 2-Hetarylquinazolin-4(3H)-ones

An efficient synthesis of 2-hetarylquinazolin-4(3H)-ones via copper-catalyzed direct aerobic oxidative amination of sp(3)C-H bonds has been developed. This tandem oxidation-amination-cyclization transformation represents a straightforward protocol to prepare 2-hetaryl-substituted quinazolinones from easily available 2-aminobenzamides and (2-azaaryl)methanes.

Metal- and Oxidant-Free Synthesis of Quinazolinones from β-Ketoesters with o-Aminobenzamides via Phosphorous Acid-Catalyzed Cyclocondensation and Selective C–C Bond Cleavage

A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-heterocycles, such as benzimidazoles and benzothiazoles.

Copper‐Catalyzed Aerobic Oxidative Inert CC and CN Bond Cleavage: A New Strategy for the Synthesis of Tertiary Amides

A copper-catalyzed aerobic oxidative amidation reaction of inert C-C bonds with tertiary amines has been developed for the synthesis of tertiary amides, which are significant units in many natural products, pharmaceuticals, and fine chemicals. This method combines C-C bond activation, C-N bond cleavage, and C-H bond oxygenation in a one-pot protocol, using molecular oxygen as the sole oxidant without any additional ligands.

Copper Catalysis for Selective Heterocoupling of Terminal Alkynes

A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.

Metal-Free Oxidative Annulation of 2-Naphthols with Terminal Alkynes Affording 2-Arylnaphtho[2,1-b]furans

For the first time, the selective oxidative transformation of 2-naphthols with terminal alkynes is disclosed, which enables the straightforward synthesis of 2-arylnaphtho[2,1-b]furans in satisfactory yields under metal-free conditions. Mechanistic study suggests that the reaction proceeds via free-radical-mediated sp(2)-C-H bond activation, C-C coupling, and C-O cyclization.

Iron-catalyzed aerobic oxidative functionalization of sp3 C–H bonds: a versatile strategy for the construction of N-heterocycles

Iron-catalyzed aerobic oxidative functionalization of sp3 C–H bonds has been developed for the construction of N-heterocycles from easily available carboxylic acid derivatives and o-substituted anilines. This transformation represents a widely applicable protocol to N-heterocycles using biofriendly iron as a catalyst in combination with molecular oxygen or air as the sole oxidant.

Catalyst-Free and Selective C-N Bond Functionalization: Stereospecific Three-Component Coupling of Amines, Dichloromethane, and >P(O)H Species Affording α-Aminophosphorus Compounds.

Catalyst-free and selective C-N bond functionalization has been achieved through three-component coupling of amines, dihalomethane, and >P(O)H species. This reaction takes place stereospecifically with retention of configuration at phosphorus, which can produce various new optically active phosphorus analogues of α-amino acids.

Synthesis, Structure and Applications of Hypervalent Organoantimony Compounds Having Intramolecular E→Sb (E = N, O, S) Coordinations

The review article covers the hypervalent organoantimony compounds that are with intramolecular N, O, SSb coordinations synthesized in the past 20 years. We describe their structures and the related coordination chemistry, highlighting a number of hyperva- lent stibines. These compounds have shown many applications in organic synthesis. They are useful reagents for reactions such as cross- coupling and arylation with organic halides, and addition with carbonyl compounds. They can be used as Lewis acid catalysts in organic synthesis. Furthermore, they can be utilized as catalysts or reagents for CO2 chemical fixation. It is envisaged that more hypervalent or- ganoantimony compounds of novel structure will be synthesized and find new applications in the near future.

Transition metal-free oxidative ortho-acylation of phenols with N-heteroarylmethanes via double C–H activation

The direct oxidative acylation of phenols with N-heteroarylmethanes via sp3C–H and sp2C–H double activation was achieved under transition metal-free reaction conditions. This transformation proceeds in a facile I2/DMSO/O2 system regio-selectively to produce valuable (2-hydroxyphenyl)arylmethanones from easily available starting materials in moderate to good yields. A plausible mechanism was proposed.