Synthesis of 2‐Aryl‐2‐hydroxyethyl Dithiocarbamates via Regioselective Addition of Tetraalkylthiuram Disulfides to Styrenes under Transition‐Metal‐Free Conditions

Conversion of Acids to S-Alkyl Dithiocarbamates by Decarboxylative Sulfuration Using Visible-Light Photocatalysis

S-Alkyl dithiocarbamates, as an important class of sulfur-containing compounds, play pivotal roles in diverse fields, yet methods for the synthesis that start from simple, readily available feedstocks and exhibit mild conditions and structurally diverse products are scarce. In this work, we developed an efficient approach for the synthesis of various S-alkyl dithiocarbamates via visible-light photocatalysis with readily available and structurally diverse alkyl carboxylic acids (primary, secondary, and tertiary acids, amino acids, etc.) and disulfide tetraalkylthiuram as the starting materials. This protocol features high efficiency, mild reaction conditions, a broad substrate scope, and good functional group tolerance. Potential applications are further demonstrated by a sunlight experiment, H2O as a solvent, gram-scale synthesis, and facile synthesis of bioactive molecules.

Visible-light induced decarboxylative coupling of phenoxyacetic acid with disulfides: synthesis of α-arylthioanisole derivatives

Photoredox-catalyzed cross-coupling reaction is an efficient strategy for the construction of organic molecules. Herein, we developed a method to synthesize α-arylthioanisoles by constructing C-S bonds in the presence of a Ru-photoredox catalyst. Thus, a series of α-arylthioanisole compounds were efficiently obtained through decarboxylative cross-coupling under mild conditions. This protocol features high efficiency, broad substrate scope and good functional group tolerance.

Copper-Catalyzed Three-Component Synthesis of β-Hydroxysulfides from Styrene Oxide, Aryl Iodide, and Carbon Disulfide

A copper-catalyzed three-component coupling reaction of styrene oxide, aryl iodide, and carbon disulfide for the construction of β-hydroxysulfides has been developed. In this process, readily available CS2 was used as the sulfur source to construct C-S bonds for the synthesis of phenyl-β-hydroxysulfides and (benzo[d]thiazol)-β-hydroxysulfides. This process features mild reaction conditions, simple operation, and wide substrate scope (>50 examples).

Metal-Free Radical [3 + 2] Annulation of Tetraalkylthiuram Disulfide with Alkynes/Alkenes: An Approach of Synthesizing 1,3-Dithiole and 1,3-Ditholane Derivatives

A novel and metal-free [3 + 2] annulation of tetraalkylthiuram disulfide with alkynes/alkenes has been developed using Selectfluor at room temperature. The formed 1,3-dithiol-2-ylium/1,3-dithiolan-2-ylium salts can be easily transformed into the corresponding 1,3-dithiol-2-ylidenes/1,3-ditholan-2-ylidenes by one-pot subsequent condensation with malononitrile. The present protocol features the use of easily accessible starting materials, mild reaction conditions, good tolerance with diverse functional groups, easy scale-up, and a wide substrate scope, affording the desired products in good yields. Importantly, this method is suitable for the late-stage modification of bioactive molecules. Furthermore, 1,3-dithiol-2-ylium salt can also be easily converted into various 1,3-dithiole derivatives by condensation, reduction, or hydrolysis. Mechanism studies show that this transformation involves radical annulation. Of note, this method presented a novel example using tetraalkylthiuram disulfide as a sulfur synthon in annulation, which greatly enriches the application of tetraalkylthiuram disulfides in organic synthesis. Biological evaluation indicates that these prepared compounds are promising candidates in terms of their antitumor activity.

Advances in Difunctionalization of Olefins with Diorganyl Dichalcogenides

Organochalcogen molecules have extensive applications in various fields. They serve as pharmaceuticals, ligands, organocatalysts, agrochemicals, and other functional materials. Difunctionalization of olefins, which belong to a class of multicomponent reactions, is a successful technique for introducing two functional moieties in a single-step reaction, both in terms of atom economy and step economy. The difunctionalization of olefins with diorganyl dichalcogenides may effectively increase the molecular complexity, which has achieved significant advancements in recent decades. This article describes recent advancements in the difunctionalization of olefins with diorganyl diselenides and diorganyl disulfides.

Nickel-Catalyzed Amidation of Aryl Alkynyl Acids with Tetraalkylthiuram Disulfides: A Facile Synthesis of Aryl Alkynyl Amides

Nickel-catalyzed amidation of aryl alkynyl acids using tetraalkylthiuram disulfides as the amine source is described, affording a series of aryl alkynyl amides in good to excellent yields under mild conditions. This general methodology provides an alternative pathway for the synthesis of useful aryl alkynyl amides in an operationally simple manner, which shows its practical synthetic value in organic synthesis. The mechanism of this transformation was explored through control experiments and DFT calculations.

One-pot two-step dithiocarbamylation of styrenes: metal-free stereoselective synthesis of styrenyl dithiocarbamates

Styrenes have been functionalized to produce styrenyl dithiocarbamates by a one-pot two-step procedure without using any metal catalysts. Styrene was transformed into a bromo-derivative, which undergoes a domino nucleophilic substitution followed by elimination in the presence of a dithiocarbamate anion and triethylamine to produce trans-styrenyl dithiocarbamates exclusively. The reaction shows a wide substrate scope and good yields of products.

Copper-Promoted Hiyama Cross-Coupling of Arylsilanes With Thiuram Reagents: A Facile Synthesis of Aryl Dithiocarbamates

We report herein a facile Hiyama cross-coupling reaction of arylsilanes with thiuram reagents (tetraalkylthiuram disulfides or tetraalkylthiuram monosulfide) enabled by copper fluoride. Compared to our previous work, this protocol is an alternative protocol for the generation of S-aryl dithiocarbamates. It features low toxic and readily available substrates, cost-effective promoter, easy performance, and provides good yields.

Visible-Light-Induced Photocatalytic Synthesis of β-Keto Dithiocarbamates via Difunctionalization of Styrenes

A facile photocatalyzed strategy for difunctionalization of styrenes in the presence of CS₂ and amines providing β-keto dithiocarbamates has been developed. In the case of 4-nitrostyrene and 2-vinylpyridine, however, only 2-arylethylthiocarbamates are interestingly formed without the aid of photoredox catalysis/TBHP.

Regioselective C-H dithiocarbamation of indolizines with tetraalkylthiuram disulfide under metal-free conditions

An efficient and straightforward metal-free regioselective C-H dithiocarbamation of indolizines with tetraalkylthiuram disulfide has been described. A series of indolizine-dithiocarbamate derivatives were easily accessed in moderate to good yields with a broad scope. In addition, imidazo[1,2-a]pyridines were also well tolerated to afford diverse imidazoheterocycle-dithiocarbamate products, which are expected to be utilized for drug discovery. Of note, the reaction could be readily scaled up, and shows its practical value in organic synthesis.