Catalyst-Free Efficient Regioselective Ring Opening of Oxiranes with Thioacids in Water

Epoxide ring opening with thioacetic acid and thiobenzoic acid was investigated in the presence of water under catalyst-free conditions. This green and simple process gave an excellent yield. With simple decanting, the products were obtained in high purity and on a large scale. In this process, alkyl halide and ester cleavage were not observed.

A Practical and Eco-Friendly Method for Conversion of Epoxides to Thiiranes with Immobilized Thiourea on CaCO3

Abstract

Solvent-free conversion of various epoxides to the corresponding thiiranes was carried out efficiently with immobilized thiourea on CaCO₃. The reactions were completed within 1–12 min under oil bath (60 °C–70 °C) conditions to afford thiiranes in 88%–98% yields.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Figures S1–S3.]

GRAPHICAL ABSTRACT      

Synthesis and antibacterial activity of novel 10, 11-epoxy acylide erythromycin derivatives

A series of novel acylide derivatives have been synthesized from clarithromycin A via a facile procedure. The C-3 modifications involved replacing the natural C-3 cladinosyl group in clarithromycin core with different aryl-piperzine sidechain via chemical synthesis. Meanwhile a distinctive intermediate with 10,11-epoxy moiety was obtained. The structure and stereochemistry of this novel structure were confirmed via NMR and X-ray crystallography. Potential anti-bacterial activities against both Grampositive and Gram-negative bacteria were reported. Because of existence of C10,11-epoxide, these derivatives can be used as intermediates for further structural modification.     

Silphos [PCl3− n (SiO2) n ]: A Heterogeneous Phosphine Reagent for the Regioselective Synthesis of vic-Haloalcohols

Silphos as a silica-based phosphine [PCl_3?n (SiO₂) _n ] provides a practical method for the conversion of epoxides to vic-haloalcohols in the presence of molecular bromine, iodine, or N-halosuccinimides (NXS, X = Cl, Br, I) in CH₃CN or under solvent-free conditions at r.t. The simple filtration of heterogeneous Silphos oxide from the reaction mixture affords the pure vic-haloalcohols with excellent yields.     

基于TiO2的绿色多相催化剂催化CO2与环氧化合物偶联反应

金属离子掺杂纳米TiO2(M-TiO2,M=Zn2+,Cu2+,Co2+,Mn2+,Ni2+)在CO2与环氧化合物的偶联反应中表现出较高的催化活性.反应以四正丁基碘化铵(TBAI)为共催化剂,在无溶剂条件下进行.考察了反应温度、反应时间和CO2压力在Zn-TiO2/TBAI体系中对反应性能的影响.作为无毒的多相催化剂,Zn-TiO2可循环使用5次,其催化活性没有明显降低.     

Recent progress toward synthesis of chlorosulfolipids: total synthesis and methodology

Chlorosulfolipids (CSLs) are an intriguing family of natural products featuring highly chlorinated linear hydrocarbon skeletons. Although CSLs were first isolated in 1962, chemical synthesis of CSLs was hampered because relevant methods for stereoselective construction of the polychlorinated motifs of CSLs were scarce. Since Carreira’s first total synthesis of the CSL mytilipin A in 2009, several groups, including our own, have reported total syntheses of CSLs. As a result of these total syntheses, important progress has been made in the development of reliable synthetic methods for stereoselective polychlorination. In this digest, we summarize the total syntheses of CSLs by focusing on synthetic methods for stereoselective polychlorination of the organic frameworks of CSLs.     

Direct conversion of epoxides into aziridines with N-arylphosphoramidates

Treatment of terminal epoxides with N-arylphosphoramidate anions leads directly to N-aryl aziridines. Existing methods for this transformation employ either multi-step syntheses or an iminophosphorane in conjunction with a Lewis acid. The described method therefore presents an advantage in terms of brevity and atom economy.     

Total Synthesis of (±)‐Clavilactones A,B, and Proposed D through Iron‐Catalyzed Carbonylation–Peroxidation of Olefin

Biologically significant clavilactones A, B, and the previously proposed D have been synthesized through iron‐catalyzed carbonylation–peroxidation of a 1,5‐diene. Three steps from aldehydes, alkenes, and tert‐butylhydroperoxide build up α,β‐epoxy‐γ‐butyrolactone skeleton as a key building block for synthesis of clavilactone family and its derivatives. Based on our results, the structure of the proposed clavilactone D is not correct and requires revision.     

2D Naphthalenedisulfonate-cadmiun coordination polymer with 2,4,5-tri（4-pyridyl）-imidazole as a co-ligand： Structure and catalytic property

A new 2D coordination polymer, [Cd（tpim）（1,5-nds）]n （1）, was constructed from 1,5-naphthalenedi- sulfonate （1,5-nds）. 2.4,5-tri（4-pyridyl）-imidazole （tpim） and Cd（CH3COO）2.2H2O, which can be subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with remarkable catalytic activity. In addition, the thermal and luminescent properties of I in the solid state were also investigated.