Qiuling Song

β-Ketophosphonate Formation via Aerobic Oxyphosphorylation of Alkynes or Alkynyl Carboxylic Acids with H-Phosphonates

A synergistic Cu/Fe-catalyzed aerobic oxyphosphorylation of alkynes or alkynyl carboxylic acids with H-phosphonate is disclosed. The useful β-ketophosphonate products were obtained in good yields under oxygen atmosphere in a novel way. This reaction exhibits a wide substrate scope, and the mechanistic experiments indicate that a radical mechanism forms both C-P and C═O bonds simultaneously. This mechanism contrasts existing aerobic difunctionalization of alkynes.

Aldehydes and Ketones Formation: Copper-Catalyzed Aerobic Oxidative Decarboxylation of Phenylacetic Acids and α-Hydroxyphenylacetic Acids

Aromatic aldehydes or ketones from copper catalyzed aerobic oxidative decarboxylation of phenylacetic acids and α-hydroxyphenylacetic acids have been synthesized. This reaction combined decarboxylation, dioxygen activation, and C-H bond oxidation steps in a one-pot protocol with molecular oxygen as the sole terminal oxidant. This reaction represents a novel decarboxylation of an sp(3)-hybridized carbon and the use of a benzylic carboxylic acid as a source of carbonyl compounds.

Synthesis of primary amides via copper-catalyzed aerobic decarboxylative ammoxidation of phenylacetic acids and α-hydroxyphenylacetic acids with ammonia in water.

A Cu2O-catalyzed aerobic oxidative decarboxylative ammoxidation to primary benzamides from phenylacetic acids and α-hydroxyphenylacetic acids is developed. A variety of primary benzamides could be prepared smoothly, in good to excellent yields, by means of a one-pot domino protocol combining decarboxylation, dioxygen activation, oxidative C-H bond functionalization, and amidation reactions.

Copper-catalyzed oxidative decarboxylative arylation of benzothiazoles with phenylacetic acids and α-hydroxyphenylacetic acids with O2 as the sole oxidant.

A Cu(II)-catalyzed oxidative decarboxylative synthesis of 2-aryl benzothiazole from phenylacetic acids and α-hydroxyphenylacetic acids has been developed. This reaction proceeds via Cu(II)-catalyzed decarboxylation, C-H bond oxidation, ring-opening, and condensation steps in a one-pot protocol with dioxygen as the sole terminal oxidant. Various functional groups were tolerated under standard conditions, and isolated yields were as high as 95%.

Sulfonamide formation from sodium sulfinates and amines or ammonia under metal-free conditions at ambient temperature

A novel, practical and highly efficient method for the construction of a variety of sulfonamides mediated by I2 was demonstrated. The reaction proceeds readily at room temperature using a variety of sodium sulfinates and amines or ammonia in water in a metal-, base-, ligand-, or additive-free protocol. Primary, secondary and tertiary sulfonamides were obtained in good to excellent yields with a broad range of functional group tolerability.

Cu-Catalyzed Aerobic Oxidative Esterification of Acetophenones with Alcohols to α-Ketoesters

Copper-catalyzed aerobic oxidative esterification of acetophenones with alcohols using molecular oxygen has been developed to form a broad range of α-ketoesters in good yields. In addition to reporting scope and limitations of our new method, mechanism studies are reported that reveal that the carbonyl oxygen in the ester mainly originated from dioxygen.

Diboron-Assisted Palladium-Catalyzed Transfer Hydrogenation of N-Heteroaromatics with Water as Hydrogen Donor and Solvent

A Pd-catalyzed transfer hydrogenation of various N-heteroaromatic compounds with B2pin2 as a mediator and environmentally benign water as both solvent and hydrogen donor has been disclosed. This reaction proceeded under ambient temperature with a broad range of N-heteroaromatic compounds among which imidazo[1,2-a]pyridine derivatives were for the first time selectively reduced to 5,6,7,8-tetrahydroimidazo[1,2-a]pyridines, which are the core structural motifs of an inhibitor of human O-GlcNAcase. Mechanistic studies suggested that the new protons in products are from water and Pd-H might be the key intermediate with B2pin2 as the H2O activator.

Fe-Catalyzed Double Cross-Dehydrogenative Coupling of 1,3-Dicarbonyl Compounds and Arylmethanes

Fe-catalyzed tandem cross-dehydrogenative coupling of the methyl group in arylmethanes with 1,3-dicarbonyl compounds has been developed. The reaction affords one new C(sp(3))-C(sp(2)) bond and one new C(sp(3))-C(sp(3)) bond in a one-pot protocol. Further study suggests that this reaction might start with a Friedel-Crafts-type reaction (cross-dehydrogenative arylation) followed by cross-dehydrogenative coupling with an activated methylene group under mild oxidative conditions.

Transition-metal-free regioselective synthesis of alkylboronates from arylacetylenes and vinyl arenes

A transition-metal-free synthesis of alkylboronates, utilizing arylacetylenes or vinyl arenes and bis(pinacolato)diboron through tandem borylation and protodeboronation, has been developed. This reaction is efficient, practical and environmentally benign, leading to anti-Markovnikov products with excellent regioselectivity, broad functional group tolerance and excellent yields in both small and gram scales.

Novel reaction patterns of carbon disulfide with organolithium compounds via cleavage of CS bonds or via cycloaddition reactions

Abstract Carbon disulfide reacted at room temperature with 1,4-dilithio-1,3-diene species via cleavage of the CS double bonds affording multiply substituted thiophenes or via cycloaddition reactions affording thiopyran-2-thiones.