Reduction of CO2 with NaBH4/I2 for the Conversion of Thiophenols to Aryl Methyl Sulfides

CO2-Promoted and Copper-Catalyzed Dehydroxylative Coupling of Benzylic Alcohols by the NaBH4/I2 System

An efficient and CO2-promoted dehydroxylative coupling of benzylic alcohols catalyzed by ligand-free cuprous chloride has been achieved. The discovered catalytic reductive coupling reaction is a newly C-C bond-forming transformation of alcohols. Mechanistic insight is gained through control reactions.

Divergent Trideuteromethylthiolation and Aminotrideuteromethylthiolation of Alkenes with N-Fluorobenzenesulfonimide and CD3SSO3Na

A metal-free oxidative trideuteromethylthiolation of alkenes with CD3SSO3Na using NFSI as an oxidant has been developed. The aminotrideuteromethylthiolation of a three-component reaction could be easily achieved in the presence of a cobalt catalyst. The divergent trideuteromethylthiolation of alkenes, readily available trideuteromethylthiolation reagent, and versatile synthetic strategy allow for late-stage modification of drug molecules.

Advancements and Challenges in Reductive Conversion of Carbon Dioxide via Thermo-/Photocatalysis

Carbon dioxide (CO₂) is the major greenhouse gas and also an abundant and renewable carbon resource. Therefore, its chemical conversion and utilization are of great attraction for sustainable development. Especially, reductive conversion of CO₂ with energy input has become a current hotspot due to its ability to access fuels and various important chemicals. Nowadays, the controllable CO₂ hydrogenation to formic acid and alcohols using sustainable H₂ resources has been regarded as an appealing solution to hydrogen storage and CO₂ accumulation. In addition, photocatalytic CO₂ reduction to CO also provides a potential way to utilize this greenhouse gas efficiently. Besides direct CO₂ hydrogenation, CO₂ reductive functionalization integrates CO₂ reduction with subsequent C-X (X = N, S, C, O) bond formation and indirect transformation strategies, enlarging the diverse products derived from CO₂ and promoting CO₂ reductive conversion into a new stage. In this Perspective, the progress and challenges of CO₂ reductive conversion, including hydrogenation, reductive functionalization, photocatalytic reduction, and photocatalytic reductive functionalization are summarized and discussed along with the key issues and future trends/directions in this field. We hope this Perspective can evoke intense interest and inspire much innovation in the promise of CO₂ valorization.

Robust, scalable construction of an electrophilic deuterated methylthiolating reagent: facile access to SCD3-containing scaffolds

We have established a practical and concise method for the straightforward access of a universal deuterated methylthiolating reagent through a one-pot gram-scale operation under mild conditions. This odourless electrophilic SCD₃ reagent was widely applied to react with numerous representative nucleophiles and approached various valuable SCD₃ analogues with excellent levels of deuterium content (>99% D). The divergent further transformations were smoothly carried out to obtain the significant derivatives with different oxidative states in high efficiency.

A Mild Heteroatom (O-, N-, and S-) Methylation Protocol Using Trimethyl Phosphate (TMP)–Ca(OH)2Combination

A mild heteroatom methylation protocol using trimethyl phosphate (TMP)–Ca(OH)2 combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.

Catalyst-free reductive cyclization of bis(2-aminophenyl) disulfide with CO2 in the presence of BH3NH3 to synthesize 2-unsubstituted benzothiazole derivatives

An efficient and catalyst-free methodology for the reductive cyclization of various disulfides using BH3NH3 as a reductant and CO2 as a C1 resource was developed.

Carbon dioxide based methodologies for the synthesis of fine chemicals

Rapid environmental changes triggered by the increase in the concentration of heat-absorbing gases such as CO2 in the atmosphere have become a major cause of concern. One of the ways to counter this growing threat will be to efficiently convert atmospheric CO2 into value-added products via the development of efficient transition-metal-catalyzed processes. Conversion of CO2 into bulk products such as CH3OH and methane as well as its incorporation into commercial polyurethane synthesis has been achieved and reviewed extensively. However, the efficient transformation of CO2 into fine chemicals and value-added chemicals has many fold advantages. Recent years have seen a rapid rise in the number of metal-mediated protocols to achieve this goal of converting CO2 into fine chemicals. These are essential developments given the requirement of several commodities and fine chemicals in various industrial processes and the utilization of atmospheric CO2 will help provide a sustainable solution to the current environmental problems. Accordingly, we present here a comprehensive compilation of catalytic processes, involving CO2 as the C1 source for reacting with substrates such as alkanes, alkenes, alkynes, amines, acid chlorides, alcohols, allyl boronates, alkenyl triflates, and many others to provide easy access to a wide variety of useful molecules. Such a technology would certainly prove to be beneficial in solving the problems associated with the environmental accumulation of CO2.

Visible-Light-Promoted Cross-Coupling Reactions of Aryldiazonium Salts with S-Methyl-d3 Sulfonothioate or Se-Methyl-d3 Selenium Sulfonate: Synthesis of Trideuteromethylated Sulfides, Sulfoxides, and Selenides

A novel visible-light-photocatalytic deuterated thiomethylation/methylselenation of aryldiazonium salts utilizing S/Se-methyl-d₃ sulfonothioate has been developed. The mild conditions and the various functional groups provide a green protocol for the efficient and rapid introduction of the S-CD₃ or Se-CD₃ group with useful levels of deuterium content (>91% D). Trideuteromethyl sulfoxides have also been successfully chemoselectively observed by simple atmospheric changes under photocatalytic conditions.