Sulfonyl Hydrazides Research Articles

Highly Selective and Switchable Access to Tetrasubstituted Alkenyl Sulfones and Naphthyl Sulfones: 1,4-Aryl Migration versus Cyclization.

A highly efficient, chemo-, and regioselective approach has been developed for the switchable synthesis of tetrasubstituted alkenyl sulfones and naphthyl sulfones from homopropargylic alcohols via sulfonylation/1,4-aryl migration and sulfonylation/cyclization. The present switchable processes are characterized by mild and metal-free conditions, high selectivities, good functional group tolerance, the use of inexpensive and easily handled sulfonyl hydrazides as sulfonyl sources, and the release of the nontoxic byproducts H2O and N2.

An Alternative Metal-Free Aerobic Oxidative Cross-Dehydrogenative Coupling of Sulfonyl Hydrazides with Secondary Phosphine Oxides

An alternative metal-free, efficient and practical approach for the preparation of phosphinothioates is established via the aerobic oxidative cross-dehydrogenative coupling (CDC) of sulfonyl hydrazides with secondary phosphine oxides catalyzed by tetrabutylammonium iodide (TBAI) in the presence of atmospheric oxygen. The strategy provides an array of diverse phosphinothioates in good to excellent yields. Furthermore, two representative bioactive molecules are synthesized on up to gram scale by utilizing this method.

Copper‐Catalyzed Sulfonyl Radical‐Enabled Regioselective Cyclization of 1,6‐Enynes

AbstractA copper‐catalyzed cascade cyclization of 1,6‐enynes with sulfonyl hydrazides for producing various sulfonyl‐substituted γ‐lactams is described. This sulfonyl radical‐enabled cyclization reaction features excellent regioselectivity, mild conditions and broad substrate scope, enabling the formation of new C−S and C−C bonds through radical sulfonylation, intramolecular cyclization and hydrogen abstraction. Moreover, relevant experiments have been carried out to probe a possible mechanism.

FeBr3-catalyzed regioselective intramolecular sulfenoamination of unactivated terminal olefins

A method for regioselective intramolecular sulfenoamination of unactivated terminal olefins was reported. Using sulfonyl hydrazides as the sulfur sources, FeBr3 as the catalyst and (NH4)2S2O8 as the oxidant, different sulfenylmethylpyrrolidines and sulfenylmethylpiperidines were obtained in moderate to high yields via intramolecular sulfenoamination of (sulfon)amidopentenes or (sulfon)amidohexenes.

Palladium‐Catalyzed Regio‐ and Stereoselective Sulfonylation of Aryl Propiolates with Sulfonyl Hydrazides: Access to (E)‐β‐Aryl Sulfonyl Acrylates

AbstractAn efficient method for the synthesis of (E)‐β‐aryl sulfonyl acrylates has been reported. This palladium‐catalyzed approach showed excellent regio‐ and stereoselectivity in the sulfonylation of aryl propiolates with sulfonyl hydrazides. Through this approach, a wide range of (E)‐β‐aryl sulfonyl acrylates were obtained in moderate to high yields.magnified image

Synthesis of Thioethers from Sulfonyl Chlorides, Sodium Sulfinates, and Sulfonyl Hydrazides

Sulfur-containing moieties, especially thioethers (sulfides), play pivotal roles in the functionalities of many natural products, pharmaceutical compounds, and organic materials. In this review, we summarize the recent synthetic protocols of thioethers using thiolating reagents, including sulfonyl chlorides, sodium sulfinates, and sulfonyl hydrazides, as the ideal starting materials. Representative mechanisms for different types of reaction are also discussed.1 Introduction2 Synthesis of Thioethers from Sulfonyl Chlorides3 Synthesis of Thioethers from Sodium Sulfinates4 Synthesis of Thioethers from Sulfonyl Hydrazides5 Conclusion

Facial synthesis of sulfinic esters via copper-catalyzed reaction of sulfonyl hydrazides with alcohols in air

The efficient Cu-catalyzed esterification of sulfonyl hydrazides with alcohols in air is described, providing sulfinic esters in good yields and broad scope. Mechanistic studies suggest that the reaction likely proceeds through free-radical formation including arylthio radical and arylsulfonyl radical, while arylsulfuric acid are the major esterification intermediate in this transformation.

Synthesis of 3,4‐Dihydrobenzo[f]phthalazines via Iodine/tert‐Butyl Hydroperoxide‐Mediated Annulation Cascade of Yne‐Allenones

AbstractAn iodine (I2)/tert‐butyl hydroperoxide (TBHP)‐mediated annulation cascade between yne‐allenones and sulfonyl hydrazides has been established, in which a wide set of dihydrobenzo[f]phthalazines were synthesized through one‐pot, two‐step strategy under metal‐free conditions. The synthetic utility of these transformations leads to subsequent C−C and C−N bond‐forming reactions to effectively build up functional aza‐heterocycle with potential significance.magnified image

Iodine-Mediated Multicomponent Synthesis of 3-Sulfenylimidazo[1,2-a]pyridines from 2-Aminopyridines, Ketones, and Sulfonyl Hydrazides

A one-pot multicomponent reaction for the synthesis of 3-sulfenylimidazo[1,2-a]pyridines from readily available 2-aminopyridines, ketones, and sulfonyl hydrazides, mediated by molecular iodine, has been developed. The transformations proceed smoothly with high efficiency and a broad substrate scope, affording the desired heterocyclic products in moderate to excellent yields.

Cu-catalyzed aerobic oxidative synthesis of sulfonamides from sulfonyl hydrazides and amines

An environmentally friendly route for sulfonamides has been developed. The oxidative coupling of sulfonyl hydrazides and amines was catalyzed by CuBr2 to produce various sulfonamides with the water and nitrogen gas as byproducts. Preliminary experiments revealed that the sulfonyl radical is likely to be involved in the reaction mechanism.

Iodine‐Promoted Synthesis of 2‐Naphthyl Thioethers from Tetralones and Sulfonyl Hydrazides

AbstractIn the traditional Bamford‐Stevens‐Shapiro‐type reaction, electrophiles replace the carbonyl group to synthesize polysubstituted carbon‐carbon double bonds. We herein report an unusually simple and general procedure to access carbon‐carbon double bonds from ketones and install electrophiles at the original α‐position of the carbonyl functional group, thus providing a new tool in organic synthesis. This reaction shows a wide substrate scope and functional‐group tolerance.

Electrochemically induced oxidative S–O coupling: synthesis of sulfonates from sulfonyl hydrazides and N-hydroxyimides or N-hydroxybenzotriazoles

The process of oxidative S-O coupling under the action of electric current was developed. Aryl, hetaryl and alkyl sulfonyl hydrazides and N-hydroxy compounds (N-hydroxyimides and N-hydroxybenzotriazoles) are applied as starting reagents for the preparation of sulfonates. The reaction is carried out under constant current conditions in an experimentally convenient undivided electrochemical cell equipped with a graphite anode and a stainless steel cathode under a high current density (60 mA cm-2). NH4Br in this process acts as a supporting electrolyte and participates in the oxidation of the starting compounds to form a coupling product. The developed strategy represents a quite atom-efficient approach: one partner loses two nitrogen and three hydrogen atoms, while another one loses only one hydrogen atom. Cyclic voltammetry and the control experiment allowed us to propose possible reaction pathways: generated through anodic oxidation molecular bromine or its higher oxidation state derivatives oxidize the starting compounds to form reactive species, which couple to form the S-O bond.

Iodine-mediated aminosulfonylation of alkenyl sulfonamides with sulfonyl hydrazides: synthesis of sulfonylmethyl piperidines, pyrrolidines and pyrazolines.

An aminosulfonylation of alkenyl sulfonamides was reported. Using iodine as the catalyst, TBHP as the oxidant, and sulfonyl hydrazides as the sulfonyl radical sources, a variety of sulfonylmethyl piperidines, pyrrolidines and pyrazolines were obtained in moderate to excellent yields.

Visible-light promoted aerobic difunctionalization of alkenes with sulfonyl hydrazides for the synthesis of β-keto/hydroxyl sulfones.

A practical method has been developed for the conversion of alkenes to β-keto/hydroxyl sulfones by their reaction with sulfonyl hydrazides under metal-free conditions. This reaction proceeds through the oxidative addition of alkenes by sulfonyl radicals that are generated by visible-light induced oxidation of sulfonyl hydrazides. Notaly the reaction uses O2 as the terminal oxidant, instead of metal catalysts or oxidants like TBHP, leading to H2O and N2 as the clean by-products. The key features of this reaction include readily available reagents, mild reaction conditions and broad substrate scope.

Iodine-catalyzed sulfonylation of sulfonyl hydrazides with tert-amines: a green and efficient protocol for the synthesis of sulfonamides.

This study provides a direct, sustainable and eco-friendly method for the synthesis of various sulfonamides via the sulfonylation of sulfonyl hydrazides with tert-amines. The method utilizes sulfonyl hydrazides to oxidize and couple with tertiary amines through selective cleavage of C–N bonds. In this reaction, molecular iodine was used as the catalyst and t-butyl hydroperoxide was used as the oxidant.

Copper-Catalyzed Aerobic Oxidative Coupling of Aromatic Sulfonyl Hydrazides with Amines:A New Access to Aromatic Sulfonamides

Copper-Catalyzed Aerobic Oxidative Coupling of Aromatic Sulfonyl Hydrazides with Amines:A New Access to Aromatic Sulfonamides

FeBr3-catalyzed regioselective hydroxysulfenylation of N-allylsulfonamides with sulfonyl hydrazides

Regioselective hydroxysulfenylation of unactivated CC double bonds was reported. Using FeBr3-bpy as the catalyst, Na2S2O8 as the oxidant, and sulfonyl hydrazides as the sulfenyl sources, hydroxysulfenylation of unfunctionalized olefins proceeded readily, giving a variety of β-hydroxysulfides in moderate to good isolated yields.

Direct Synthesis of Benzo[ f]indazoles from Sulfonyl Hydrazines and 1,3-Enynes by Copper-Catalyzed Annulation.

A novel and efficient strategy for the direct synthesis of benzo[ f]indazoles via copper-catalyzed cascade reaction of sulfonyl hydrazides with 1,3-enynes under mild conditions has been developed. This method achieves the formation of two C-N bonds and one C-C bond in one pot, providing a series of benzo[ f]indazoles in moderate to good yields with good functional group tolerance and remarkable regioselectivity.

Solvent Controlled Transformation between Sulfonyl Hydrazides and Alkynes: Divergent Synthesis of Benzo[b]thiophene‐1,1‐dioxides and (E)‐β‐iodo Vinylsulfones

AbstractA green, efficient and controllable transformation between sulfonyl hydrazides and alkynes leading to benzo[b]thiophene‐1,1‐dioxides and (E)‐β‐iodo vinylsulfones via radical pathway has been developed. The reaction occurs rapidly in the presence of simply H2O2 and KI without the help of any transition metal. The chemoselectivity of the reaction is determined by the solvent in which the process is performed: TFE favors the cyclic product, while H2O medium generates the iodosulfonylative product. Notably, this protocol also represents the first direct approach to the aggregation‐induced‐emmision (AIE) active benzo[b]thiophene‐1,1‐dioxides from readily available sulfonyl hydrazides and alkynes in one step.magnified image

N‐Iodosuccinimide as Bifunctional Reagent in (E)‐Selective C(sp2)−H Sulfonylation of Styrenes

AbstractHerein we report the use of N‐iodosuccinimide (NIS) as a bifunctional reagent for a regio‐ and (E)‐selective C(sp2)‐H sulfonylation reaction of styrenes. Styrenes and sulfonyl hydrazides treated with NIS and potassium carbonate in ethanol at 70 °C resulted in (E)‐vinyl sulfones exclusively with good to excellent yields. NIS, plays a dual role to generate sulfonyl radical from sulfonyl hydrazides at an initial stage and finally gives β‐iodosulfone intermediate which was further converted to (E)‐vinyl sulfones. Overall, a sustainable method for mild, metal free, convenient, one pot and direct synthesis of (E)‐vinyl sulfones from styrenes are demonstrated via a C−S coupling reaction.