Practical preparation of N-(1-alkynyl)sulfonamides and their synthetic utility in titanium alkoxide-mediated coupling reactions

Aliphatic and aromatic sulfonamides were alkynylated with 1-bromo-1-alkynes in the catalytic presence of CuI to give N-(1-alkynyl)sulfonamides in good to excellent yields. Racemization of optically active sulfonamides was not observed during this alkynylation. The acetylene-titanium complexes generated from the resultant N-(1-alkynyl)sulfonamides and Ti(O-i-Pr)₄/2 i-PrMgCl underwent regio-, olefinic stereo-, and diastereoselective addition to aldehydes to give virtually single allyl alcohols. Alternatively, inter- or intramolecular coupling reaction between N-(1-alkynyl)sulfonamides and another acetylene or olefin with the above titanium alkoxide reagent generated the corresponding titanacycles, hydrolysis of which furnished stereo-defined (sulfonylamino)dienes or cyclic compounds.     

Coupling reactions of bromoalkynes with imidazoles mediated by copper salts: synthesis of novel N-alkynylimidazoles

A cross-coupling reaction of imidazoles with bromoalkynes in the presence of a catalytic amount of CuI is reported. This protocol allows an access to novel N-(1-alkynyl)imidazoles in moderate to good yields.     

N-(吡啶-2-基羰基)取代芳基磺酰胺的合成及除草活性

N-(吡啶-2-基羰基)取代芳基磺酰胺的合成及除草活性     

Control of the regioselectivity of sulfonamidyl radical cyclization by vinylic halogen substitution

The radical cyclization reactions of unsaturated sulfonamides were investigated. The photolysis of N-(4-halo-4-pentenyl)sulfonamides (X=I, Br, or Cl) with (diacetoxyiodo)benzene (DIB) and iodine at room temperature afforded exclusively the corresponding piperidines in 73-98% yield via 6-endo radical cyclization. On the other hand, the reactions of N-(5-halo-4-pentenyl)sulfonamides with DIB/I2 led to the only formation of the pyrrolidine products in 84-99% yield via 5-exo radical cyclization. The vinylic halogen substitution not only successfully inhibits the competing ionic iodocyclization process to allow the radical cyclization to proceed smoothly but also shows a remarkable effect in controlling the regioselectivity of cyclization.     

Tandem reaction of propargylic alcohol, sulfonamide, and N-iodosuccinimide: synthesis of N-(2-iodoinden-1-yl)arenesulfonamide

An efficient and straightforward strategy for the synthesis of N-(2-haloinden-1-yl)arenesulfonamides from propargylic alcohols and sulfonamides is described. Allenesulfonamide is postulated to be the key intermediate for this tandem transformation.     

Acid-catalyzed intramolecular cyclization of N-(4,4-diethoxybutyl)sulfonamides as a novel approach to the 1-sulfonyl-2-arylpyrrolidines

Herein we report our studies on the acid-catalyzed cyclisation of N-(4,4-diethoxybutyl)sulfonamides at the presence of polyatomic phenols as an efficient one-pot approach to the synthesis of 1-sulfonyl-2-arylpyrrolidines from the acyclic precursors.     

Catalytic asymmetric cleavage of sp3 C-N bonds for access to highly enantioenriched N-benzylic sulfonamides

In the presence of 10 mol% of a chiral phosphoric acid, a variety of racemic N-benzylic sulfonamides having N-(3-indolyl)methyl groups smoothly undergo kinetic resolution with benzyl thiol at 0 °C or at room temperature and the remaining sulfonamides are recovered in moderate to excellent yields and with excellent ee.     

Synthesis, structure, and reaction of 1-alkynyl(aryl)-lambda3-bromanes

Reported here for the first time are the synthesis, structure, and reaction of hypervalent 1-alkynyl(aryl)-lambda3-bromanes. BF3-catalyzed ligand exchange on bromine(III) of p-trifluoromethylphenyl(difluoro)-lambda3-bromane with 1-alkynyl(trimethyl)stannanes in dichloromethane at -78 degrees C afforded 1-alkynyl(aryl)-lambda3-bromanes in good yields. Trimethyl(trimethylsilylethynyl)stannane gave silylethynyl-lambda3-bromane selectively. 13C NMR chemical shifts of acetylenic carbon atoms of alkynylbromanes are compared with those of alkynyl-lambda3-iodanes and explained in terms of the spin-orbit-induced heavy atom effects. The structure of tert-butylethynylbromane was established by a single-crystal X-ray analysis of its crown ether complex. The 1-alkynyl(aryl)-lambda3-bromanes serve as highly electron-deficient Michael acceptors and undergo tandem Michael-carbene rearrangements by the reaction with sulfonate anions, yielding 1-alkynyl sulfonates.     

Convenient procedure for the preparation of alkyl and aryl substituted N-(aminoalkylacyl)sulfonamides

A convenient synthesis of N-(aminoalkylacyl)sulfonamides from CBZ potected glycine, β-alanine and GABA is described.     

Proline Sulfonamide-Based Organocatalysis: Better Late than Never

The history of proline sulfonamides for use in catalyzing highly enantioselective and diastereoselective C-C bond forming reactions is described. Highlighted is the development of N-(p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide ("Hua Cat") and N-(carboxy-p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide ("Hua Cat-II") by Yang and Carter. Specific reactions covered include the aldol reaction, Mannich reaction, formal aza-Diels-Alder reaction, tandem Michael/Mannich reaction and Yamada-Otani reaction. The ability of proline aryl sulfonamides to construct all-carbon quaternary stereocenters in high enantioselectivity and diastereoselectivity is a notable feature of the reported work. The practicality of this chemistry for large scale and industrial applications is also included. Finally, a discussion of the future directions of proline sulfonamide organocatalysis is provided.     

A Convenient Synthesis of N-Functionalized Perfluoroalkanesulfonamides

This article describes the synthesis of new N-functionalized perfluoroalkanesulfonamides (5) with two sulfonamides functionalities. Perfluoroalkanesulfonyl fluoride underwent a reaction with 2-chloroethylamine hydrochloride or 3-bromopropylamine hydrobromide to give N-(2-chloroethyl or 3-bromopropyl) perfluoroalkanesulfonamides (1). Reaction of (1) with potassium thiocyanate gave N-(2-thiocyanatoethyl or 3-thiocyanatopropyl) perfluoroalkanesulfonamides (3). The sulfonyl chloride derivatives (4) were prepared by reaction of 3 with sulfuryl chloride. In the last step, 4 reacted with ammonia to give the bis sulfonamides derivatives (5). The structures of all new compounds prepared were determined by ¹H, ¹⁹F, and ¹³C NMR spectroscopies and by HR-MS.     

Rh(III)-catalyzed oxidative olefination of N-(1-naphthyl)sulfonamides using activated and unactivated alkenes

Rhodium(III)-catalyzed oxidative olefination of N-(1-naphthyl)sulfonamides has been achieved at the peri position. Three categories of olefins have been successfully applied. Activated olefins reacted to afford five-membered azacycles as a result of oxidative olefination-hydroamination. Unactivated olefins reacted to give the olefination product. 2-fold oxidative C-C and C-N coupling was achieved for allylbenzenes.     

Synthesis of 1-alkynyl(diphenyl)onium salts of group 16 elements via heteroatom transfer reaction of 1-alkynyl(phenyl)-lambda 3-iodanes

1-Alkynyl(phenyl)-lambda 3-iodanes undergo selective transfer of the alkynyl groups over the phenyl group onto diphenyl chalcogens. Exposure of 1-alkynyl(phenyl)-lambda 3-iodanes to diphenyl chalcogens (S, Se, and Te) in dichloromethane or 1,2-dichloroethane affords 1-alkynyl(diphenyl)sulfonium, -selenonium, and -telluronium salts in high yields.     

Tandem Michael addition-carbene insertion reaction of 1-alkynyl(aryl)(tetrafluoroborato)-lambda3-bromanes: 1-(phenylsulfonyl)- and 1-(trifluoromethylsulfonyl)cyclopentene annulation

Exposure of 1-alkynyl[p-(trifluoromethyl)phenyl](tetrafluoroborato)-lambda(3)-bromanes to sodium benzenesulfinate or sodium trifluoromethanesulfinate in dichloromethane at 0 degree C under argon resulted in tandem Michael-carbene insertion reactions to produce 1-sulfonylcyclopentenes selectively, with concomitant formation of a small amount of rearranged 1-alkynyl sulfones.     

Synthesis and properties of a new kind of one-dimensional conductor VIII. Synthesis and characterization of trans-bis-1-alkynyl substituted silicon,germanium, tin phthalocyanines and germanium hemiporphyrazines

The preparation of several new trans-bis-1-alkynyl(phthalocyaninato)silicon (VIc—f), -germanium (VIIc—f) and -tin (VIIId, f) compounds as well as trans-bis-1-alkynyl(hemiporphyrazinato)germanium (XIc, e, f) derivatives is described. The products were obtained in high yields by treating the corresponding dichlorides (I, II, IV, X; X = (Cl) with 1-alkynyl Grignard reagents (Vc—f) in tetrahydrofuran (THF) and were characterized spectroscopically. The compounds obtained are considered as models for a new kind of one-dimensional conductor.     

Domino Michael addition-carbene rearrangement-cyclization reaction of 1-alkynyl(aryl)-lambda3-bromanes with 2-mercapto-1,3-benzazoles

Exposure of 1-alkynyl[p-(trifluoromethyl)phenyl](tetrafluoroborato)-lambda3-bromanes to 2-mercaptobenzimidazole or benzothiazole in dichloromethane at 0 degrees C under argon resulted in a domino Michael addition-carbene rearrangement-cyclization reaction to produce directly tricyclic heterocycles in high yields, whereas the reaction with 2-mercaptobenzoxazole afforded 1-alkynyl sulfides.     

Studies on hydrozirconation of 1-alkynyl sulfoxides or sulfones and the application for the synthesis of stereodefined vinyl sulfoxides or sulfones

The hydrozirconation reaction of 1-alkynyl sulfoxides or sulfones with Cp2Zr(H)Cl in THF at room temperature predominantly gave Z-beta-zirconated vinyl sulfoxides or sulfones with excellent regioselectivity. Compared with 1-alkynyl sulfoxides, the hydrozirconation reaction of 1-alkynyl sulfones exhibits great synthetic potential, leading to the efficient preparation of Z-beta-halovinyl sulfones, Z-beta-sulfonyl alpha,beta-unsaturated ketones, and Z-beta-alkynyl vinyl sulfones. Although the reaction mechanisms are still not clear, the neighboring group participation of the sulfinyl or sulfonyl group may be playing an important role in this unique hydrozirconation reaction.     

Pd-catalyzed sulfinylzincation of activated alkynes with 1-alkynyl sulfoxides as a sulfinyl source

Unprecedented Pd-catalyzed sulfinylzincation with 1-alkynyl sulfoxide as a sulfinyl source was developed. Bis-sulfinyl alkenes were formed in good yields on treatment of 1-alkynyl sulfoxides with Et(2)Zn in the presence of a Pd-catalyst, wherein zinc sulfenate (or sulfinylzinc) species would be generated in situ to undergo highly syn-selective conjugate addition to the 1-alkynyl sulfoxides. By using 3,3-dimethyl-1-butynyl sulfoxides, formation of the bis-sulfinyl alkenes was completely suppressed and the sulfinylzincation of activated alkynes was accomplished. The reaction tolerates various functionalities, and was promoted considerably by the neighboring group participation of the heteroatom at the delta-position in the alkynoates. Stereodivergent synthesis of two diastereomeric vinylic sulfoxides and reaction of the resulting vinylzinc species with electrophiles were also described.     

Synthesis of 1-sulfonyl-2-arylpyrrolidines via intramolecular cyclization/Mannich-type reaction cascade of N-(4,4-diethoxybutyl)sulfonamides

Abstract

Herein, we report the successful application of a novel approach to 2-substituted pyrrolidines based on intramolecular cyclization/intermolecular Mannich-type cascade reaction of N-(4,4-diethoxybutyl)sulfonamides to the synthesis of pyrrolidines possessing heterocyclic and polyaromatic moieties. The proposed approach benefits from mild reaction conditions, moderate to high yields of target compounds and provides a convenient route to the previously unknown 1-sulfonyl-2-arylpyrrolidines.     

Regioselective synthesis of cytotoxic 4-(1-alkynyl)-substituted 2-(5H)-furanones

4-(1-Alkynyl)-3-bromo- and 4-(1-alkynyl)-3-chloro-2(5H)-furanones have been regioselectively synthesized in moderate to good yields by a new version of the Pd/Cu-catalyzed Sonogashira reaction involving treatment of 1-alkynes with 3,4-dibromo- and 3,4-dichloro-2(5H)-furanone, respectively, in the presence of KF as a base. 4-(1-Alkynyl)-3-bromo-2(5H)-furanones have been found to be able to undergo Stille-type and Suzuki-type reactions with aryl(tributyl)tins and arylboronic acids, respectively, to give 4-(1-alkynyl)-3-aryl-2(5H)-furanones in modest to satisfactory yields. Some 4-(1-alkynyl)-substituted 2(5H)-furanones so prepared have been found to exhibit significant cytotoxic activities, especially against human leukemia cell lines.