Electrophilic addition to norbornene derivatives containing CF<Subscript>3</Subscript> and NO<Subscript>2</Subscript> groups

Electrophilic sulfenylation, selenenation, and halogenation of bicyclo[2.2.1]heptenes containing CF₃ or NO₂ group in position endo-5 were studied. The sulfenylation and selenenation were accomplished by arylsulfene- and arylselenenamides activated by POHal₃ (Hal = Br, Cl), and iodination was performed by KICl₂. The reactions are regiospecific and involve an exo-attack of the electrophilic fragment (arylthio or arylseleno group or iodine) on the C=C bond atom located closer to the CF₃ or NO₂ group. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1445–1448, June, 2005.     

Asymmetric sulfenylation of 3-CF3-Oxindoles through organocatalysis with a quinidine derivative

An asymmetric sulfenylation of 3-CF₃-oxindoles catalyzed by a quinidine derivative was described. 3-CF₃-oxindoles with electro-donating groups led to corresponding products in good yield and with good enantioselectivity while 3-CF₃-oxindoles bearing electro-withdrawing groups were not competent substrates due to its significant decomposition at the optimal reaction conditions. As for the sulfenylation reagents based on thiophenol, both electro-donating groups and electro-withdrawing groups were well tolerated.     

Metal Free Mono‐ and 2,3‐Bis‐sulfenylation of Indoles in Water with Sodium Sulfinates as a Sulfur Source

An iodine‐PPh₃ mediated sulfenylation of indoles in water with stable and odorless sodium sulfinates as the sulfur source is described. The reaction could afford monosulfenylated indoles in moderate to excellent yields under metal free conditions. Moreover, double C—H sulfenylation of indoles at 2‐ and 3‐positions has also been achieved by using excess sodium sulfinates under the optimized reaction conditions.     

A Unified Strategy for Arylsulfur(VI) Fluorides from Aryl Halides: Access to Ar-SOF3 Compounds

A convenient protocol to selectively access various arylsulfur(VI) fluorides from commercially available aryl halides in a divergent fashion is presented. Firstly, a novel sulfenylation reaction with the electrophilic N-(chlorothio)phthalimide (Cl-S-Phth) and arylzinc reagents afforded the corresponding Ar-S-Phth compounds. Subsequently, the S(II) atom was selectively oxidized to distinct fluorinated sulfur(VI) compounds under mild conditions. Slight modifications on the oxidation protocol permit the chemoselective installation of 1, 3, or 4 fluorine atoms at the S(VI) center, affording the corresponding Ar-SO₂F, Ar-SOF₃, and Ar-SF₄Cl. Of notice, this strategy enables the effective introduction of the rare and underexplored -SOF₃ moiety into various (hetero)aryl groups. Reactivity studies demonstrate that such elusive Ar-SOF₃ can be utilized as a linchpin for the synthesis of highly coveted aryl sulfonimidoyl fluorides (Ar-SO(NR)F).     

NH4I/1,10-phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl arylsulfinates

An efficient synthesis of N-heterocyclic aryl sulfides via NH₄I/1,10-phenanthroline-catalyzed direct sulfenylation reactions was reported. In this reaction, heteroarenes such as indoles, and pyrroles serve as nucleophiles by installing a arylthio group at the C3 and C2 position of heterocycles, respectively. With readily accessible and free of unpleasant odor ethyl arylsulfinates as sulfur reagents, the metal-free-catalyzed direct sulfenylation of N-heteroarenes has been developed. 3-Arylthio-indoles and 2-arylthio-pyrroles derivatives were obtained in moderate to excellent yields, even on gram scale. The reaction was general for a broad scope of substrates and demonstrated good tolerance to a variety of functional groups.     

Microwave-assisted and catalyst-free sulfenylation of imidazo[2,1-b]thiazoles with sulfonyl hydrazides in water

Abstract

An efficient microwave-assisted and catalyst-free sulfenylation of imidazo[2,1-b]thiazoles with sulfonyl hydrazides has been developed in water. This method is practical and environmental friendly, and can be performed within a short reaction time. The sulfenylation reaction shows high regioselectivity, and excellent functional-group compatibility, giving the desired products in moderate to good yields.     

Fluorinated Isocyanates and Their Derivatives as Intermediates for Biologically Active Compounds

Fluorinated aromatic isocyanates are valuable intermediates for the production of herbicides and insecticides. Unexpected rearrangements during the synthesis of 2-(trifluoromethyl)phenyl isocyanates provide an entry to N-trifluoromethylaminobenzoyl fluorides, a novel class of compounds having fungicidal properties. Carbamoyl fluorides, the products of HF addition to isocyanates, undergo ready sulfenylation. Use of these intermediates for the synthesis of N-sulfenylcarbamate insecticides led to the discovery of the new principle of detoxification of carbamates by sulfenylation.     

Mild synthesis of N-acylsulfenamides from arylamides and disulfides

An efficient and new method was developed to synthesize N-acylsulfenamides via NaH-promoted sulfenylation of benzamides with readily available disulfides under mild conditions. A series of N-acylsulfenamides were easily obtained in moderate to high yields. Moreover, the obtained N-acylsulfenamides were used as thiolating reagents in the synthesis of sulfenylpyrroles and 3-sulfenylbenzofurans.     

Sunlight Induced and Recyclable g-C3N4 Catalyzed C-H Sulfenylation of Quinoxalin-2(1H)-Ones

A sunlight-promoted sulfenylation of quinoxalin-2(1H)-ones using recyclable graphitic carbon nitride (g-C₃N₄) as a heterogeneous photocatalyst was developed. Using the method, various 3-sulfenylated quinoxalin-2(1H)-ones were obtained in good to excellent yields under an ambient air atmosphere. Moreover, the heterogeneous catalyst can be recycled at least six times without significant loss of activity.     

Asymmetric Synthesis of Chiral α‐Substituted Mercaptoglycine Derivatives via α‐Sulfenylation of Ni(II) Complex of Glycine and S‐Substituted 4‐Methylbenzenesulfonothioate

The asymmetric α ‐sulfenylation of Ni(II ) complex of glycine with S ‐substituted 4‐methylbenzenesulfonothioate is reported. Due to the mild and simple reaction conditions, this asymmetric reaction is compatible with various functional groups.     

Imination of Sulfur-containing Compounds: XXXV. New Preparation Method and Oxidative Benzenesulfonylimination of Unsymmetrical Disulfides

A new preparative method of synthesis was developed for unsymmetrical, symmetricaldisulfides consisting in sulfenylation of sodium thiolates with N-arenesulfenyl-N,N'-bis(arenesulfonyl)sulfin-amidines. Imination of unsymmetrical disulfides with sodium chloroamides of sulfonic acids occurs at the more nucleophilic sulfur atom affording N,N'-bis(arenesulfonyl)sulfinamidines and symmetrical disulfides.     

HBr/H2O2-mediated formation of C–S bond with thiosulfates

A novel, efficient, and green protocol to construct C–S bond has been developed via HBr/H₂O₂-mediated sulfenylation of styrenes and 4-hydroxycoumarins leading to unsymmetrical sulfides. Various unsymmetrical sulfides were prepared in one step with moderate to good yields using environmentally-friendly H₂O₂ as oxidant and HBr as catalyst. Based on the preliminary experimental results, a plausible reaction mechanism was proposed for HBr/H₂O₂-mediated formation of C–S bond with thiosulfates.     

Copper(I)‐Catalyzed Interrupted Click/Sulfenylation Cascade: One‐Pot Synthesis of Sulfur Cycle Fused 1,2,3‐Triazoles

Herein, we report a practical protocol for the synthesis of sulfur cycle fused 1,2,3‐triazoles through a copper(I)‐catalyzed tandem click/intramolecular sulfenylation reaction. The reaction proceeded via a copper‐catalyzed alkyne azide cycloaddition, followed by interception of the in situ formed cuprate‐triazole intermediate with p‐toluenesulfonothioate. This reaction shows broad substrate scope, complete regioselectivity, and excellent functional group tolerance under mild reaction conditions.     

Reactions of arensulfenamides with olefins in the presence of picric acid

N-(2- and 4-Nitrophenylthio)morpholines in the presence of equimolar amounts of picric acid enter into the reaction of electrophilic sulfenylation of the C=C norbornene bond to give bi- and tricyclic sulfides. With cyclohexene,trans-2-arylthiocyclohexanol are formed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1661–1663, August, 1998.     

Reactions of 1,3,3,3-tetrafluoro-2-methoxycarbonylpropenesulfenyl chloride with enamines

1,3,3,3-Tetrafluoro-2-methoxycarbonylpropenesulfenyl chloride readily reacts with enamines (derivatives of -oxo acids) to give sulfenylation products. The reactions with N-aryl-substituted enamines are accompanied by cyclization to form N-aryl-2-(2,2,2-trifluoro-1-methoxycarbonylethylidene)-2,3-dihydrothiazoles.     

Reaction of bicyclo[2.2.1]hepta-2,5-diene with the arenesulfenamide—phosphorus(v) oxohalide system: chemo-, regio-, and steroselectivity

The chemo-, regio- and stereoselectivities of electrophilic sulfenylation of bicyclo[2.2.1]hepta-2,5-diene with arenesulfenamides activated by phosphorus(v) oxohalides were studied. The ratio of the products of endo- to exo-attack of the diene by the electrophilic species depends on the solvent nature. The proportions of the products formed upon addition to one double bond and upon homoallylic participation of the second double bond depend on solvent polarity, the nature of the halogen, the substituents in the sulfenamide benzene ring, and on the reaction time. In addition, the formation of mixed adducts was proven for the reaction carried out in acetonitrile and the formation of disulfenylation products was found in the reaction with excess sulfenylating reagent. Isomerization of exo-3-arylthio-endo-2-halobicyclo[2.2.1]hept-5-enes to the products formed with homoallylic participation of the second double bond, exo-5-arylthio-endo-3-halotricyclo[2.2.1.0^2,6]heptanes, was shown to be possible.     

Desymmetrization of 2,2′,6,6′-tetramethoxybiphenyl by regioselective sulfenylation reaction

A practical regioselective sulfenylation reaction of the achiral title compound 1 provides desymmetrization and access to C₂-symmetric sulphur derivatives. Resolution of 2,2′,6,6′-tetramethoxy-3,3′-dimercapto-1,1′-biphenyl 7 was achieved by conversion to the corresponding dithiocarbonate diastereomers. The absolute configuration of (aR)-(−)-7 and (aS)-(+)-7 was assigned unambiguously.     

Iodine-promoted direct sulfenylation of 2,3-dihydroimidazo[2,1-b]thiazoles with disulfides

A novel and facile method for the direct sulfenylation of 2,3-dihydroimidazo[2,1-b]thiazoles with disulfides has been developed. The transformation is promoted by iodine under metal-free conditions, providing the corresponding products in moderate to good yields.     

Total Synthesis of (+)‐MPC1001B

The first total synthesis of an epidithiodiketopiperazine alkaloid, (+)‐MPC1001B, was accomplished. This synthesis features a tetra‐n‐butylammonium fluoride mediated intramolecular aldol reaction for forming the 15‐membered macrolactone ring, and the construction of an epidithiodiketopiperazine substructure through a stepwise sulfenylation reaction involving a novel trityl trisulfide (TrSSS)‐group transfer.     

Sulfenylation Reaction of Some α-Phosphoryl Sulfoxides

Abstract

Some α-methylsulfanyl phosphorylsulfoxides were obtained by sulfenylation reaction in homogeneous phase.