A new strategy for the chemoselective sulfonamide N-alkylation of sulfonyl ureas under neutral and mild conditions

An efficient and chemoselective sulfonamide N-alkylation of sulfonyl ureas is described. The sulfonyl urea derivatives, prepared in situ by the addition of an amine to an arylsulfonyl isocyanate, are selectively alkylated in excellent yields under neutral and mild conditions by treatment with trialkylphosphite-dimethyl acetylenedicarboxylate at ambient temperature.     

Selective formation of 1,5-substituted sulfonyl triazoles using acetylides and sulfonyl azides

The reaction of acetylides with sulfonyl azides was found to selectively form 1,5-substituted sulfonyl triazoles. This reaction thus provides access to the regioisomeric product as compared to the popular copper-catalyzed azide-alkyne cycloaddition. The reaction is efficient and selective with a variety of alkyne sources and sulfonyl azides and can incorporate an additional electrophile to yield 1,4,5-trisubstituted sulfonyl triazoles.     

Rhodium-catalyzed intermolecular amidation of arenes with sulfonyl azides via chelation-assisted C-H bond activation

We report the direct amidation of arene C-H bonds using sulfonyl azides as the amino source to release N(2) as the single byproduct. The reaction is catalyzed by a cationic rhodium complex under external oxidant-free conditions in the atmospheric environment. A broad range of chelate group-containing arenes are selectively amidated with excellent functional group tolerance, thus opening a new avenue to practical intermolecular C-N bond formation.     

An efficient preparation of new sulfonyl fluorides and lithium sulfonates

An efficient preparation of several polyfluoroalkanesulfonyl fluorides is reported. This method, based on the synthesis of polyfluoroalkyl trimethyl silanes (precursors of polyfluoroalkylsulfinates) as intermediates, allows the successive transformations to be carried out in one pot. Moreover, these sulfonyl fluorides can be obtained from the corresponding sulfinates by electrophilic fluorination. This original approach avoids isolation and purification of some thermally or hydrolytically unstable intermediates. A series of new sulfonyl fluorides have been thus prepared from halogenodifluoromethylated precursors RCF2X (X = F, Br; R = ArC(O), ArS(O)n(CF2)m; n = 0, 1, 2; m = 1, 2) and have been transformed into the corresponding lithium sulfonates, which have potential applications as electrolytes for lithium batteries.     

Glycosylated N-sulfonylamidines: highly efficient copper-catalyzed multicomponent reaction with sugar alkynes, sulfonyl azides, and amines

Copper-catalyzed multicomponent reactions with sugar alkynes, sulfonyl azides, and amines to furnish glycosylated N-sulfonylamidines are reported. The reaction is established to be general in terms of different combinations of sugar alkyne, sulfonyl azide, and amines.     

Convenient synthesis of sulfonyl azides using PEG-400 as an efficient and eco-friendly reaction medium

Sulfonyl azides have efficiently been synthesized via a convenient and environmentally benign procedure, in which sulfonyl chlorides undergo nucleophilic substitution reaction with sodium azide in PEG-400 under mild conditions. The sulfonyl azides were obtained in 84–97% isolated yields.

     

An improved and efficient procedure for the preparation of chiral sulfinates from sulfonyl chloride using triphenylphosphine

An improved procedure of the Sharpless method for the preparation of chiral sulfinates by triphenylphosphine is described. A mixture of sulfonyl chlorides and diacetone-d-glucose or l-menthol in the presence of triethylamine was treated with triphenylphosphine in CH₂Cl₂ at 0°C to give the sulfinates in good yields.     

Radical amination with sulfonyl azides: a powerful method for the formation of C-N bonds

A novel reaction for the introduction of an azide moiety by means of a mild radical process is currently under development. Sulfonyl azides are suitable azidating agents for nucleophilic radicals, such as secondary and tertiary alkyl radicals. More electrophilic radicals, such as enolate radicals, do not react with sulfonyl azides. This feature allowed the development of efficient intra- and intermolecular carboazidations of olefins. Due to the versatility of the azido group, this reaction has an important synthetic potential, as already demonstrated by the preparation of the core of several alkaloids, particularly those containing an amino-substituted quaternary carbon center, such as FR901483.     

Highly efficient coupling of beta-substituted aminoethane sulfonyl azides with thio acids, toward a new chemical ligation reaction

[reaction: see text] A highly efficient coupling of protected beta-substituted aminoethane sulfonyl azides with thio acids is reported. In the case of peptide thio acids, this method encompasses a new chemoselective ligation method. Furthermore, the resulting alpha-amino acyl sulfonamides can be alkylated with suitable electrophiles to obtain densely functionalized sulfonamide scaffolds.     

Sterically biased 3,3-sigmatropic rearrangement of azides: efficient preparation of nonracemic alpha-amino acids and heterocycles

[reaction: see text] Homochiral alpha-amino acids, heterocycles, and carbocycles are efficiently constructed via a short sequence of reactions starting from the chiral auxiliary p-menthane-3-carboxaldehyde. The key feature of the sequence is a highly selective tandem Mitsunobu/3,3-sigmatropic rearrangement of hydrazoic acid that procures enantiomerically enriched allylic azides. The sequence is either terminated by oxidative cleavage to provide amino acids or by ring-closing metathesis to provide heterocycles or carbocycles bearing nitrogen.     

The reversed Kenner linker: a new safety-catch linker for the preparation of N-alkyl sulfonamides

A new strategy for the solid-phase synthesis of sulfonamides is described. The Kenner safety-catch strategy has been modified such that the carboxylic acid component remains attached to the solid support while the sulfonamide portion is released into solution. An initial demonstration of the scope of this strategy is presented, along with an analysis of the cleavage characteristics and extension to more elaborate products via Suzuki reaction and thiazolidinone synthesis. Reaction: see text.     

Simple and facile method for the preparation of vinyl azides

A synthetic utility of [bis(trifluoroacetoxy)iodo]benzene on α,β-unsaturated carboxylic acid is described. This is the first example of preparation of vinyl azide using α,β-unsaturated carboxylic acids directly by using hypervalent iodine reagent. The advantage of this protocol is characterized with non-toxicity of starting material and shorter reaction times to obtain good preparative yields. The method is also useful for the preparation of acyl azides.     

A novel approach for the formation of carbon-nitrogen bonds: azidation of alkyl radicals with sulfonyl azides.

Two preparatively attractive methods for the azidation of alkyl radicals are described. Secondary and tertiary alkyl iodides and dithiocarbonates are easily converted into the corresponding azides, either by reaction with ethanesulfonyl azide in the presence of dilauroyl peroxide, or by treatment with benzenesulfonyl azide and hexabutylditin in the presence of a radical initiator. Interestingly, intramolecular tandem radical cyclization-azidation processes can be performed in high yields.     

A fast and efficient method for the preparation of aryl azides using stable aryl diazonium silica sulfates under mild conditions

An efficient, fast, and straightforward procedure for the synthesis of aromatic azides using aryl diazonium silica sulfates and sodium azide at room temperature under mild conditions is described. The use of inexpensive materials, simple and clean work-up, short reaction times and good yields are advantages of this method.     

Resin-bound 4-phenyl-1,2-dihydroquinoline (DHQ): a new safety-catch linker for solid-phase organic synthesis (SPOS)

A new safety-catch linker has been developed for combinatorial solid-phase chemistry. Azidomethyl-polystyrene, obtained by nucleophilic substitution of chloromethyl-polystyrene, undergoes an acid promoted Schmidt rearrangement. The resulting polymer-bound iminium participates in an aza Diels-Alder cycloaddition, which leads to a supported dihydroquinoline (DHQ resin). The acylated form of the DHQ resin is stable under basic, acidic and mild reducing agents. The cleavage proceeds in two steps (i) oxidative aromatization leading to an activated quinolinium and (ii) nucleophilic displacement of the quinoline resin. The overall process is high yielding and efficient.     

The preparation and reactions of polymeric azides. II. The preparation and reactions of various polymeric azides

Polymeric haloethyl acrylates, methacrylates, and methacrylamides, poly(vinyl chloride), poly-(epichlorohydrin), and halohydrins prepared from poly(glycidyl methacrylate), poly(butadiene), and poly(pentenamer) were converted to the corresponding azides. These azides reacted with a variety of acetylenic and olefinic derivatives to give, in most cases, good conversions to the corresponding triazole derivatives.     

Click chemistry: a new facile and efficient strategy for preparation of functionalized HPLC packings

Click chemistry has been successfully extended into the field of preparation of functionalized HPLC packings, proving a novel facile and efficient strategy for covalently bonding stationary phases onto HPLC grade silica beads; the potential has been demonstrated by the preparation of "Click I-IV" columns and preliminary results in the separation of sugars.     

One-pot synthesis of 5-sulfonamidopyrazole from terminal alkynes, sulfonyl azides and hydrozones

5-Sulfonamidopyrazoles were efficiently synthesized from terminal alkynes, sulfonyl azides and hydrozones. The sequential reaction involves a copper-catalyzed three-component reaction, a Lewis acid-catalyzed electrocyclic reaction and a dehydrogenation.