α-Fluorination of β-ketosulfones by Selectfluor™ F–TEDA–BF4

Photoredox-Catalyzed α-Sulfonylation of Ketones from Sulfur Dioxide and Thianthrenium Salts

A photoredox-catalyzed sulfonylation of silyl enol ethers with DABCO·(SO₂)₂ and thianthrenium salts is achieved, providing diverse β-keto sulfones in moderate to good yields. This protocol features easily accessible starting materials and good functional group compatibility, enabling the introduction of various functionalized sulfonyl groups into ketones. Furthermore, as one of the important industrial raw materials, methanol can be employed as the methyl source to prepare α-methylsulfonated ketones through a methyl thianthrenium intermediate for the first time.

Efficient Monofluoroalkylation of Thiophenols or Phenols with α-Bromo-α-Fluoroketones under Mild Conditions

An efficient nucleophilic substitution reaction between α-bromo-α-fluoroketones and thiophenols or phenols is reported for the synthesis of α-fluoro-β-ketosulfides or α-fluoro-β-ketone ethers in yields ranging from 78–93%. This method exhibits good functional group tolerance and a broad scope of nucleophilic substrates, including natural phenolic compounds.

Catalytic AgF-Initiated Intramolecular 1,3-Sulfonyl Migration of gem-Difluorovinyl Sulfonates to α,α-Difluoro-β-ketosulfones

A 1,3-sulfonyl migration of difluorovinyl sulfonates initiated by a catalytic amount of silver fluoride is presented. α,α-Difluoro-β-ketosulfones were successfully prepared in excellent yields. This method features high chemoselectivity, good functional group tolerance, high atom economy, and mild, environmentally benign reaction conditions. Furthermore, mechanistic experiments indicate that this migration proceeds in an intermolecular pathway and the corresponding sulfinates are possible intermediates.

Synthesis of benzofurans from the cyclodehydration of α-phenoxy ketones mediated by Eaton’s reagent

Cyclodehydration of α-phenoxy ketones promoted by Eaton’s reagent (phosphorus pentoxide–methanesulfonic acid) is used to prepare 3-substituted or 2,3-disubstituted benzofurans with moderate to excellent yields under mild conditions. The method provides a facile access to benzofurans from readily available starting materials such as phenols and α-bromo ketones. The reaction is highly efficient, which is attributed to the good reactivity and fluidity of Eaton’s reagent. The reaction can be applied to prepare naphthofurans, furanocoumarins, benzothiophenes, and benzopyrans.

Sulfated tungstate/dioxygen: a new catalytic system for oxysulfonylation of styrenes to form β-keto sulfones

A new green cat./O₂ oxidation system is mild, safe, heterogeneous, simple to make, stable, noncorrosive, produces N₂ as by product, and has an easy to recover–reuse catalyst and wide substrate scope.

Photoredox-catalyzed sulfonylation of difluoroenoxysilanes with the insertion of sulfur dioxide

A photoredox-catalyzed three-component reaction of aryldiazonium tetrafluoroborates with sodium metabisulfite and 2,2-difluoro enol silyl ethers is described, providing α,α-difluoro-β-ketosulfones in moderate to good yields under mild conditions.

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

The copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid is reported. The procedure operates under simple conditions to afford the corresponding aryl cyclopropyl sulfides in moderate to excellent yields. The reaction tolerates substitution in ortho-, meta- and para-substitution as well as electron-donating and electron-withdrawing groups. The S-cyclopropylation of a thiophenol was also accomplished using potassium cyclopropyl trifluoroborate.

Divergent Regio- and Stereoselective Gold-catalyzed Synthesis of α-Fluorosulfones and β-Fluorovinylsulfones from Alkynylsulfones

We developed a widely applicable, highly efficient synthesis of α-fluorosulfone and β-fluorovinylsulfone catalyzed by gold. Starting with alkynyl sulfone 1, an [Au]/HF/N-oxide system gives α-fluorosulfone 3 via a gold carbene intermediate, and, if no N-oxide is used, direct addition of HF to 1 gives vinyl sulfone 4 via a vinylfluoro gold intermediate. Both methods have good functional group tolerance and the reactions can be conducted in ambient atmosphere.

Synthesis of o-Methyl Trifluoromethyl Sulfide Substituted Benzophenones via 1,2-Difunctionalization of Aryne by Insertion into the C-C Bond

An efficient process for the preparation of valuable o-methyl trifluoromethyl sulfide substituted benzophenones has been developed. The transition-metal-free method features insertion of aryne into a C-C σ-bond under mild reaction conditions for the first time to achieve ortho-difunctionalized arenes containing a pharmaceutically important trifluoromethylthio functional group. A wide substrate scope has been demonstrated for the developed protocol.

A direct approach for the expedient synthesis of unsymmetrical ethers by employing bromodimethylsulfonium bromide (BDMS) mediated C–S bond cleavage of naphthalene-2-ol sulfides

Synthesis of unsymmetrical ether derivatives using 1-(aryl(alkyl/arylthio)methyl)-naphthalene-2-ol and alcohols in the presence of bromodimethylsulfonium bromide (BDMS).

Tetrabutylammonium iodide-catalyzed oxidative coupling of enamides with sulfonylhydrazides: synthesis of β-keto-sulfones

A novel synthetic route toward pharmaceutically interesting β-keto-sulfone derivativesviaTBAI/TBHP-mediated oxidative coupling of readily prepared enamides with sulfonylhydrazides is described.

Copper-catalyzed coupling of oxime acetates with sodium sulfinates: an efficient synthesis of sulfone derivatives

Sulfone derivatives are important synthetic intermediates. However, the general method for their preparation is through traditional coupling reaction: the alkylation of sodium sulfinates with phenacyl halides. Based on our previous work on sodium sulfinates and oxime acetates, we herein report a novel method for sulfone derivatives by oxidative coupling with sodium sulfinates and oxime acetates using copper as catalyst. The sulfonylvinylamine products could be formed in excellent yields. Upon hydrolysis by silica gel in CH2 Cl2 , β-ketosulfones could also be efficiently constructed. Various sulfonylvinylamines and β-ketosulfones were obtained in good to excellent yields under the optimized reaction conditions. Mechanistic studies indicated that this transformation involved copper-catalyzed N-O bond cleavage, activation of a vinyl sp(2) C-H bond, and C-S bond formation. The oxime acetates act as both a substrate and an oxidant, thus the reaction needs no additional oxidants or additives.

Selective monofluorination of active methylene compounds: the important role of ZnCl2 in inhibiting overfluorination

ZnCl₂ effectively facilitates selective monofluorination of methylene compounds by inhibiting the undesired overfluorination.

On the Configurational Stability of Chiral Heteroatom-Substituted [D1]Methylpalladium Complexes as Intermediates of Stille and Suzuki-Miyaura Cross-Coupling Reactions

Enantiomerically pure (S)-tributylstannyl[D1]methanol and (R)- and (S)-tributylstannyl[D1]methyl benzoates were Stille-coupled with bromobenzene and benzoyl chloride in 1,4-dioxane and toluene using [(Ph3P)4Pd] or [(Ph3P)2PdCl2] either alone or in combination with CuCN as cocatalyst at temperatures up to 80 °C. The products were found to be enantiomerically pure. (R)- and (S)-N-(tributylstannyl[D1]methyl)phthalimides gave enantiomerically pure products with benzoyl chloride, but with bromobenzene protected phenyl[D1]methylamines gave products of only 52-69 % ee depending on the solvent used. Tributyl(thio[D1]methyl)stannanes could not be Stille-coupled with benzoyl chloride or with bromobenzene. Similarly, dimethyl phenyl[D1]methylboronate underwent a Suzuki-Miyaura coupling with bromobenzene to give phenyl[D1]methylsilane with 99 % ee. All couplings followed a retentive course and, except in one case, the intermediate [XCHDPdL n ] complexes were found to be microscopically configurationally stable.

Synthesis of chiral cyclic nitrones by asymmetric addition of β-ketosulfones to nitroalkenes followed by reductive cyclization

The first organocatalytic addition of β-ketosulfones to nitroalkenes catalyzed by thiourea cinchona alkaloids is presented. The readily obtained addition products were selectively transformed into chiral nitrones by reduction of the nitro group and in situ cyclization (up to 99:1 e.r. and >98:2 d.r.). Moreover, the utility of this method has additionally been demonstrated by the further transformation to functionalized N-hydroxypyrrolidines that possess a quaternary center by addition of trimethylsilyl cyanide (TMSCN) to the C=N bond of the cyclic nitrones in the presence of a Lewis acid.

2-(Benzo[d]thiazol-2-ylsulfonyl)-1-(4-bromophenyl)ethanone

In the title mol­ecule, C₁₅H₁₀BrNO₃S₂, the dihedral angle between the benzothia­zole ring system and the benzene ring is 67.57 (12)°. The crystal structure is stabilized by weak inter­molecular C—H⋯O inter­actions. In addition, there is an inter­molecular Br⋯C [3.379 (3) Å] contact which is shorter than the sum of the van der Waals radii of these atoms.

Synthesis of fluorinated beta-ketosulfones and gem-disulfones by nucleophilic fluoroalkylation of esters and sulfinates with di- and monofluoromethyl sulfones

An efficient and practically useful method for the preparation of alpha-functionalized mono- and difluoro(phenylsulfonyl)methanes by using a nucleophilic fluoroalkylation methodology was developed. Alpha,alpha-difluoro-beta-ketosulfones, alpha-monofluoro-beta-ketosulfones, and alpha-fluoro disulfones were successfully prepared in excellent yields by nucleophilic fluoroalkylation of esters and sulfinates with PhSO(2)CF(2)H and PhSO(2)CH(2)F reagents.