Search

A novel tactic for the regioselective O-alkylation of 2-pyridones has been realized through palladium catalysis facilitated by silver carbonate in moderate to high yields, the coordination effect between palladium and nitrogen on the pyridine ring plays a versatile role.

An effective regiodivergent synthesis toward 1- and 3-thiosugars was achieved through palladium and cobalt catalysis, respectively. β-1-Thiosugars were obtained from 3,4-O-carbonate-glycals and var...

An exclusive asymmetric reduction of CO bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (−)-goniomitine.

A new methodology of stereoselective C-glycosylation has been developed with 3,4-O-carbonate glycals and boronic acids, catalyzed by 1,2-bis(phenylsulfinyl)ethane palladium(II) acetate under open-air conditions at room temperature. This mild method is simple in operation, wide in substrate range, and tolerant in alcoholic/phenolic hydroxyl and amino groups. High to excellent yields were observed for all substrates tested, with the driving force mainly contributed by decarboxylation. Meanwhile, the high 1,4-trans-selectivity was achieved by steric effects as proposed.

An inexpensive and effective cobalt coordinated conjugated microporous polymer (Co-CMP-2) made up from cross-linked an ethanediamine-based salen ligand with 1,3,5-triethynylbenzene. Co-CMP-2 exhibited extremely high catalytic efficiency in the synthesis of cyclic carbonates from CO2 and epoxides, which is superior to that of previously reported Co-CMP. Co-CMP-2 achieved a TOF of 23300 h−1 for ethylene carbonate. Moreover, the catalyst can be reused more than 10 times without significant loss in activity.

Covalent triazine-based frameworks (CTFs) are important microporous materials with a wide range of applications. Here, we demonstrate an environmentally benign and economic synthetic pathway to CTFs. The monomers used for CTFs, aromatic nitriles, were obtained by cyanation using nontoxic potassium hexacyanoferrate (Ⅱ) in place of commonly used toxic cyanides. Then, the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride. A series of CTFs was synthesized, and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m 2 /g. Among the synthesized CTFs, CTF DCP exhibited excellent CO 2 adsorption properties, with a CO 2 uptake of 225 mg/g at 0℃.

A novel gold-catalyzed C-glycosylation has been developed to gain access to α,(Z)-selective C-vinyl glycosides, starting from readily available glycals and propargylic carboxylate. This reaction involves a tandem intermolecular gold-catalyzed 1,3-acyloxy migration/Ferrier rearrangement with the involvement of allenic ester as the glycosyl acceptor. A wide range of substrate scope with good to excellent yields was achieved with complete diastereoselectivity. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version We thank the Ministry of Education (MOE 2013-T3-1-002), National Research Foundation (NRF2016NRF-NSFC002-005), Nanyang Technological University, Singapore (RG14/16), China Scholarship Council (No. 201508420062), and Youth Talent Development Foundation of China Three Gorges University for their financial support. Dr. Yongxin Li and Dr. Ganguly Rakesh in the division of chemistry and biological chemistry, Nanyang Technological University are also acknowl-edged for X-ray analysis.

Zinc-coordinated conjugated microporous polymers (zn-cmps), prepared by linking salen zinc and 1,3,5-triethynylbenzene, exhibit extraordinary activities (turnover frequencies of up to 11600 h(-1)), broad substrate scope, and group tolerance for the synthesis of functional organic carbonates by coupling epoxides with co2 at 120 degrees c and 3.0 mpa without the use of additional solvents. the catalytic activity of zn-cmp is comparable to those of homogeneous catalysts and superior to those of other heterogeneous catalysts. this catalyst could be reused more than ten times without a significant decrease in performance.

We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.

The catalyst is reused for more than ten times without significant loss of its catalytic activity.