A Palladium-Catalyzed Decarboxylative Heck-Type Reaction of Disubstituted Vinylphosphonates in the Stereoselective Synthesis of Trisubstituted Vinylphosphonates

Synthesis of alkenylphosphine oxides via Tf2O promoted addition-elimination of ketones and secondary phosphine oxides

Herein, we describe an efficient method for the synthesis of alkenylphosphine oxides via a Tf2O promoted addition-elimination process. Various diarylphosphine oxides and alkylarylphosphine oxides react with ketones smoothly and produce alkenylphosphine oxides in moderate to excellent yields with abundant functional group compatibility. In addition, several transformations and applications of the product also demonstrate the potential value of the methodology.

Cationic Iridium-Catalyzed Decarboxylation of Aromatic Carboxylic Acids

Practical synthetic applications of catalytic decarboxylation in producing useful molecules are limited. We report herein the cationic Ir-catalyzed decarboxylations of various electron-rich and -poor aromatic carboxylic acids to produce hydrocarbons in good yield (up to >99%). Additionally, this reaction is applicable in decarboxylative hydroarylation of bicyclic alkenes and decarboxylative fluorination, indicating the potential utility of this catalytic decarboxylation in synthetic chemistry.

Preparation of Vinylphosphonates from Ketones Promoted by Tf2O

An efficient triflic anhydride promoted phosphorylation of ketone was disclosed, and vinylphosphorus compounds were prepared under solvent- and metal-free conditions. Both aryl and alkyl ketones could perform smoothly to give vinyl phosphonates in high to excellent yields. In addition, the reaction was easy to carry out and easy to scale up. Mechanistic studies suggested that this transformation might involve nucleophilic vinylic substitution or a nucleophilic addition-elimination mechanism.

Markovnikov-addition of H-phosphonates to terminal alkynes under metal- and solvent-free conditions

An addition of H-phosphonates to aryl alkynes was realized under solvent- and metal-free conditions, affording Markovnikov-selective α-vinylphosphonates in moderate to good yields. A wide range of aryl alkynes could be applied for the reaction. A tentative mechanism of addition-substitution was proposed based on in situ 31P {1H} NMR studies.

α-Hydroxy acid as an aldehyde surrogate: metal-free synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and other N-heterocycles via decarboxylative oxidative annulation reaction

A metal-free and efficient procedure for the synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and indolo[1,2-a]quinoxaline has been developed. The key features of our method include the in situ generation of aldehyde from α-hydroxy acid in the presence of TBHP (tert-butyl hydrogen peroxide), and further condensation with various amines, followed by intramolecular cyclization and subsequent oxidation to afford the corresponding quinoxalines, quinazolinones derivatives in moderate to high yields.