Synthesis of cis-1,2-dichlorovinylsulfones via Fe-catalyzed regio- and stereoselective addition of sulfonyl chlorides to aromatic chloroalkynes

An iron-catalyzed regio- and stereoselective chlorosulfonylation of aryl chloroalkynes has been described, producing cis-1,2-dichlorovinylsulfones in satisfactory yields with good to excellent stereoselectivity (Z/E up to 95:5). A variety of functional groups such as F, NO₂, Cl, Br, OMe, and t-Bu are found to be compatible under the reaction conditions.     

TBAI-mediated regioselective sulfenylation of indoles with sulfonyl chlorides in one pot

A versatile method for the synthesis of 3-sulfenylated indoles via TBAI promoted sulfenylation of indoles with sulfonyl chlorides in one pot has been presented. This system features highly regioselective, metal-free, easy operation, and shows a broad functional group tolerance leading to excellent yields. And this reaction could be easily conducted in 10?mmol scale with high effectivity. A plausible mechanism is proposed.     

Microwave Assisted Synthesis of Sodium Sulfonates Precursors of Sulfonyl Chlorides and Fluorides

We describe the use of a microwave reaction for the conversion of various bromides to sodium sulfonates that have been further elaborated to sulfonyl chlorides. This new approach leads to much improved yields and shorter reaction times. Representative sulfonyl chlorides serve as precursors for the respective sulfonyl fluorides that are potent inhibitors of the fatty acid amide hydrolase.     

Direct coupling of haloquinolines and sulfonyl chlorides leading to sulfonylated quinolines in water

A simple and efficient method has been developed for construction of sulfonylated quinolines via coupling of haloquinolines and sulfonyl chlorides in water. The present methodology provides an attractive approach to various sulfonylated quinolines in moderate to good yields with favorable functional group tolerance, which has the advantages of operation simplicity, readily available starting materials, excellent regioselectivity, scale-up synthesis, and organic solvent-free conditions.     

Prevention of anode fouling during the electrochemical perfluorination of aromatic carboxylic acid chlorides

The electrochemical perfluorination of benzoyl chloride, p-substituted benzoyl chlorides and cyclo-hexane carboxylic acid chloride in anhydrous hydrogen fluoride (AHF) medium on nickel electrode is reported. Experimental conditions suppressing polymeric film formation on the electrode are optimized. Addition of 1 wt.% dimethyl sulfide based on the volume of AHF in the initial stage of electrochemical fluorination and maintenance of the reactant and intermediate concentrations below a critical level ensured electrochemical fluorination of all the reactants without fouling of the electrode surface. Presence of p-substituents in the benzene ring improved the selectivity of alicyclic perfluoro carboxylic acid. GC/MS and ¹⁹F NMR data for the major perfluorinated products are reported.     

Visible-light-induced direct oxysulfonylation of alkynes with sulfonyl chlorides and HCl

A mild, practical and efficient strategy to prepare β-keto sulfones has been developed by visible-light-induced reactions. This reaction involved Ir(dtbbpy)(ppy)₂PF₆-catalyzed direct functionalization of alkynes with sulfonyl chloride and HCl using air as the oxidant. HCl not only acted as a hydrogen source in the proton transfer process, but also played a vital role in the reaction process.     

Silver(I)-mediated reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides:Unexpected formation of vinvl sulfones

A novel reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides was performed in the presence of silver nitrate or triflate.Conjugated vinyl sulfones as dramatic products were obtained in moderate yields and with Z-selectivity.A free radical mechanism has been proposed to account for the formation of the products.     

Synthesis of some novel sulfonyl ester derivatives derived from d-mannitol

The preparation of sulfonate-derivatives of d-mannitol i.e. 1,2:3,4-di-O-isopropylidene-3,4-di-O-p-toluenesulfonate-d-mannitol (3a), 1,2:3,4-di-O-isopropylidene-3,4-di-O-methanesulfonate-d-mannitol (3b), and 1, 2:3,4-di-O-isopropylidene-3,4-di-O-trifluoromethanesulfonate-d-mannitol (3c) is described. Full characterization and methodologies of these sulfonate-d-mannitol derivatives have been described as well.     

Palladium-catalyzed desulfinylative Negishi C-C bond forming cross-couplings of sulfonyl and organozinc chlorides

Arene-, phenylmethane- and alkenesulfonyl chlorides are suitable electrophilic reagents in desulfinylative carbon-carbon bond formation cross-coupling reactions with organozinc reagents.     

Regioselective Synthesis of Polyheterocycles From 4-Cyclohex-2-ENYL-3-Hydroxy-1-Methylquinolin-2(1H)-One

4-Cyclohex-2-enyl-3-hydroxy-1-methylquinolin-2(1H)-one (4) was prepared in 90% yield by the thermal [3,3]sigmatropic rearrangement of 3-cyclohex-2-enyloxy-1-methylquinolin-2(1H)-one (3) in refluxing chloroben-zene for 10 h. Compound (4) was cyclised through a sequence of reactions viz. i) acetylation ii) addition of bromine and iii) treatment of the acetyl dibromo compound (6) with base to give a bicyclic product (7) in 90% yield. Treatment of compound 4 with pyridine hydro-bromide perbromide in dichloromethane at 0–5° C afforded a cyclic product 8 in excellent yield. Compound 4 when treated with cold conc. sulphuric acid at 0–5° C furnished the bicyclic product 12 in 89% yield.     

Synthesis of sulfonimide-based dendrimers and dendrons possessing mixed 1 → 2 and 1 → 4 branching motifs

The synthesis of dendrimers and a chlorosulfo-dendron possessing a unique combination of 1?→?2 and 1?→?4 branching types is described. The procedure consists of a two-step preparation of 3,5-dinitrobenzene-1-sulfonyl chloride, which was used for the persulfonylation of p-toluidine and 4-(benzylthio)aniline. The obtained tetranitro compounds were reduced to the corresponding tetraamines. The latter were decorated with eight 4-toluene sulfonyl groups each to furnish the corresponding dendrimers. Oxidation of the dendrimer possessing a 4-(benzylthio)phenylene core with N-chlorosuccinimide resulted in the formation of a dendron with a sulfonyl chloride functionality at the focal point.     

Bromodifluoromethylation of aromatic Grignard reagents with CF2Br2

The bromodifluoromethylation of aromatic Grignard reagents having electron-withdrawing groups with dibromodifluoromethane (CF₂Br₂) was developed. The reaction proceeded to give the corresponding (bromodifluoromethyl)benzene derivatives via a difluorocarbene-mediated mechanism.     

Chemoselective Acetalization of Carbonyl Compounds1

Chemoselective protection of carbonyl compounds as acetals has been carried out by using Envirocat EPZG as a novel heterogeneous catalyst.     

Synthesis of pyrazoles from 2-azidoacrylates and hydrazonyl chlorides

A regioselective synthesis of 1,3,4,5-tetrasubstituted pyrazoles is established between 2-azidoacrylates and hydrazonyl chlorides in the presence of triethylamine. The yields are moderate (43-73%) and a possible mechanism for this transformation is postulated.     

Mizoroki-Heck type arylation of alkenes using aroyl chlorides under base-free conditions

The Mizoroki-Heck type arylation of alkenes with aroyl chlorides accompanied by decarbonylation efficiently proceeds in the presence of a palladium catalyst system, PdCl₂(PhCN)₂/(PhCH₂)Bu₃NCl, even without adding any base. The products can be isolated by a very simple procedure.     

Palladium-catalyzed reactions of arylboron compounds with carboxylic acid chlorides

Reactions of sodium tetraarylborates and arylboronic acids with acyl chlorides in the presence of palladium salts afford non-symmetrical ketones in high yields under mild conditions.     

A Metal‐Free Synthesis of 2‐Alkyl(or Aryl) Thiomethyl‐2‐cyclohexenones from Cyclic Morita–Baylis–Hillman Bromides

Under mild conditions, an efficient and rapid S‐allylation of thiols with cyclic Morita–Baylis–Hillman (MBH) bromides without the need of a transition‐metal catalyst or an expensive additive is described herein. Treatment of the MBH bromides with various thiols or ethane‐1,2‐dithiol in the presence of Et₃N regioselectively affords the corresponding 2‐alkyl(or aryl) thiomethyl‐2‐cyclohexenones or the perhydro benzo[1,4]dithiepinone, respectively, in moderate to good yields (40 – 73%). The reaction is rapid and carried out in THF at room temperature.     

A Synthesis of 9-Methoxy-1-Methyl-1H,6H-Pyrazolo[4,3-c]Carbazole

The synthesis of 9-Methoxy-1-methyl-1H,6H-pyrazolo[4,3-c]carbazole is reported in four steps from 6-nitroindazole. Palladium acetate mediated cyclization gave only the “bent” tetracyclic derivative.     

Palladium-catalyzed desulfinylative C-C allylation of Grignard reagents and enolates using allylsulfonyl chlorides and esters

2-Methylprop-2-ene-, prop-2-ene-, 1-methylprop-2-ene-, and (E)-but-2-enesulfonyl chlorides have been used as electrophilic partners in desulfinylative palladium-catalyzed C-C coupling with Grignard reagents and sodium salts of dimethyl malonate and methyl acetoacetate. Neopentyl alk-2-ene sulfonates can also be used as electrophilic partners in desulfinylative allylic arylations and allylic alkylations. The regioselectivity of the allylic arylation and alkylation depends on the nature of the catalyst. With PdCl₂(PhCN)₂, (E)-crotyl derivatives are formed in high regioselectivity using either 1-methylprop-2-ene- or (E)-but-2-enesulfonyl chloride.