Efficient sulfonylation of ketones with sodium sulfinates for the synthesis of β-keto sulfones

The oxidative sulfonylation of ketones with sodium sulfinates as the sulfone source and DMSO as the oxidant is reported. A series of β-keto sulfones were obtained in good to excellent yields. The advantages of this efficient protocol include the low cost of DMSO and HBr, and a broad scope.     

Rongalite-promoted synthesis of β-keto sulfones via radical cascade reaction

Direct arylsulfonylation of arylethenes with aryl iodides and sodium metabisulfite to access β-keto sulfones is described. In this reaction, rongalite (sodium hydroxymethanesulfinate) and sodium metabisulfite serve as the radical promoter and the sulfur dioxide surrogate, respectively.     

Reactions of cyanofurazans with β-dicarbonyl compounds

In the presence of nickel acetylacetonate, -dicarbonyl compounds readily add at the nitrile group of 4-R-3-cyanofurazans to form enaminofurazans. The adducts obtained from 4-amino-3-cyanofurazan underwent intramolecular cyclization on heating with AcOH in EtOH to give furazano[3,4-b]pyridine derivatives in high yields.     

NBS-mediated synthesis of β-keto sulfones from benzyl alcohols and sodium arenesulfinates

An efficient synthetic route towards the synthesis of β-keto sulfones has been developed from secondary benzyl alcohols using N-bromosuccinimide (NBS). The present protocol utilizes NBS as oxidant as well as brominating agent, readily accessible benzyl alcohols and sodium arenesulfinates as the sulfonylating reagent under mild conditions. The control experiments revealed that the reaction proceeds via oxidation of alcohol to ketone, α-bromination of ketone and nucleophilic substitution by sodium arenesulfinate. Furthermore, the efficiency of the methodology was tested with a gram scale reaction and also shown the synthetic utility.     

Reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds

The reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds give 1,2,4-triazepino [2,3-a]benzimidazole and pyrimido [1,2-a]benzimidazole-derivatives.     

Enantioselective bioreduction of β-keto sulfones with the fungus Curvularia lunata

β-Keto sulfones bearing bulky groups are reduced with high enantioselectivities to the corresponding optically active β-hydroxy sulfones by the fungus Curvularia lunata CECT 2130; the cells can be re-used without loss of their catalytic activity.     

Enantioselective hydrogenation of β-keto sulfones with chiral Ru(II)-catalysts: synthesis of enantiomerically pure butenolides and γ-butyrolactones

A series of β-hydroxy sulfones were synthesized with high enantioselectivities via a new enantioselective ruthenium-catalyzed hydrogenation using MeO-BIPHEP as a ligand. Some β-hydroxy sulfones were used in the synthesis of optically active butenolides and γ-butyrolactones with high yields and enantioselectivities over 95%.     

The facile insertion of β-keto sulfones to arynes: The direct preparation of polysubstituted ortho-keto benzyl sulfones

One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.     

Efficient synthesis of γ-keto sulfones by NHC-catalyzed intermolecular Stetter reaction

The N-heterocyclic carbene-catalyzed intermolecular Stetter reaction of aldehydes with α,β-unsaturated sulfones allows the atom-economic and selective formation of γ-keto sulfones in good yields. Key to the success of this unique transition-metal-free carbon-carbon bond-forming reaction is the right choice of the NHC precursor and base. The reaction tolerates a broad range of different aldehydes.     

Reactions of β-aminopropionic acid N"-acylhydrazides with carbonyl compounds

The reactions of -aminopropionic acid N"-acylhydrazides with aromatic and heterocyclic aldehydes and acetone afford compounds that exist in solutions predominantly as mixtures of 2-substituted 3-acylaminotetrahydropyrimidin-4-ones (ATHP) and tautomeric Schiff"s bases. These compounds in the crystalline state probably have structures of ATHP. The ratio of tautomers depends on the type of substituent in the aromatic ring and solvent. The reactions of 2-aryl-3-benzamidotetrahydropyrimidin-4-ones with carboxylic or sulfonic acid chlorides afford derivatives of 1-acyl- and 1-tosyl-3-benzamidotetrahydropyrimidin-4-ones.     

Practical synthesis of β-acyl and β-alkoxycarbonyl heterocyclic sulfones

A short and efficient synthesis for β-acyl and β-alkoxycarbonyl heterocyclic sulfones containing benzothiazol (BT) and phenyltetrazol (PT) heterocyclic core is presented here. The method seems to be general and provides the desired C-nucleophiles in very good to excellent yields from readily available starting materials.     

K2S2O8-mediated decarboxylative oxysulfonylation of cinnamic acids: A transition-metal-free synthesis of β-keto sulfones

A new paradigm of the oxidative decarboxylative sulfono functionalization of cinnamic acids with sulfinate salts mediated by K₂S₂O₈ under aerobic conditions to afford synthetically and biologically relevant β-keto sulfones has been described. It is the first report on the transition-metal-free synthesis of β-keto sulfones from cinnamic acids, which employs environmentally benign, readily available and inexpensive starting materials and oxidants, viz. air and K₂S₂O₈.     

The facile insertion of β-keto sulfones to arynes： The direct preparation of polysubstituted ortho-keto benzyl sulfones

One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.     

Visible-light-promoted oxidative difunctionalization of alkenes with sulfonyl chlorides to access β-keto sulfones under aerobic conditions

A mild, practical and efficient strategy to prepare β-keto sulfones has been developed by visible light promoted reactions. This reaction involves Ir(ppy)₂(dtbbpy)PF₆ catalyzed direct funcationalization of alkenes with sulfonyl chlorides under mild conditions. Air was used as oxidant without any additives. The transformation affords the corresponding products in moderate to high yields.     

A facile stereospecific synthesis of chiral β-keto sulfoxides

A synthetic strategy has been devised for the preparation of chiral β-keto sulfoxides (actually, α-vinylsulfinyl ketones) starting from the readily available C-6 substituted 2,3-dihydro-1,4-oxathiines. The procedure, which is characterized by high yields and excellent enantiomeric excesses, represents an improvement in preparation methods for chiral β-keto sulfoxides.     

PMA-SiO2 catalyzed synthesis of β-keto enol ethers

An efficient conversion of β-diketones into correspondingβ-keto enol ethers with catalytic amount of PMA-SiO_2 has been achieved.     

Synthesis and chemical properties of cyclic β-keto sulfones (review)

Published data on the synthesis and chemical properties of dihydrothiophen-3(2H)-one 1,1-dioxide, dihydro-2H-thiopyran-3(4H)-one 1,1-dioxide, 1-benzothiophen-3(2H)-one 1,1-dioxide, and 1H-isothio-chromen-4(3H)-one 2,2-dioxide are reviewed. The choice of subjects was based on the presence of identical structural fragments, carbonyl, active methylene, and sulfonyl groups.     

MnIII-catalyzed phosphorylation of vinyl azides: The synthesis of β-keto phosphine oxides

Mn^III-catalyzed functionalization of vinyl azides via phosphorylation was developed to synthesize various β-keto phosphine oxides in high yields. The transformation is operated in mild conditions and tolerant of a range of functional groups. Control reaction indicates that the reaction mechanism might proceed via the generation of a phosphonated iminyl radical intermediate.     

Aerobic oxysulfonylation of alkynes in aqueous media: highly selective access to β-keto sulfones

The first application of inexpensive commercially available sulfinate salts to produce β-keto sulfones directly from alkynes via aerobic oxysulfonylation has been developed. It is a highly selective (undesired Glaser–Hay homo-coupling and ATRA process totally suppressed) general method of functionalization of alkynes on water at room temperature involving FeCl₃/K₂S₂O₈ catalyzed formation of sulfonyl radicals from sulfinate salts.     

One-step synthesis of differently bis-functionalized isoxazoles by cycloaddition of carbamoylnitrile oxide with β-keto esters

A new protocol for synthesizing different functionalized isoxazoles is provided. Carbamoylnitrile oxide generated from nitroisoxazolone underwent inverse electron-demand 1,3-dipolar cycloaddition with 1,3-dicarbonyl compounds in the presence of magnesium acetate that formed magnesium enolate in situ. Although electron-deficient trifluoroacetoacetate did not undergo this cycloaddition under the same conditions, conversion to sodium enolate furnish the corresponding bis-functionalized trifluoromethylisoxazole. The DFT calculations using B3LYP 6-31G+(d,p) also supported the aforementioned reactivity.