微波辐射促进N－烷基化邻硝基苯胺的合成

报道了微波辐射促进芳香氯与胺衍生物的亲核取代反应，应用这一新的有效合 成方法能以50％－99％的产率快速合成N－烷基化邻硝基苯胺构建单元。     

Microwave promoted synthesis of functionalized 2-aminothiazoles

Microwave irradiation promotes the rapid one-pot synthesis of 2-aminothiazoles fromed via the condensation of α-bromoketones with thiourea.     

Diastereoselective reductive imino-aldol reaction of alpha-imino esters promoted by titanium tetraiodide: synthesis of alpha,beta-diamino esters

Under the influence of titanium tetraiodide reductive imino-aldol reaction of the N-tosylimine derived from ethyl glyoxylate proceeded with aldimines to give alpha,beta-diamino esters in good yields in a highly diastereoselective manner.     

Microwave and ultrasound promoted synthesis of substituted new arylhydrazono pyridinones

A variety of arylhydrazonopyridinones 6a,b were prepared via heating cyanoacetamide derivative with ethyl acetoacetate in the absence of solvent under reflux conventionally or ultrasound irradiation or in a microwave oven then coupling with heteroaromatic diazonium salts. Several attempts were made to synthesize corresponding aminothienopyridinones 7a,b from 6a,b. Also, attempts to add electron poor olefins to 6a,b have failed and only arylhydrazonopyridinones recovered.     

二碘化钐促进的 β-碲代酯(腈)的合成

本文报道在室温, 中性介质中研究二碘化钐在合成中的应用. 在二碘化钐作用下,二碲醚发生Te-Te键还原断裂, 生成碲负离子物种, 后者再与α,β-不饱和酯(腈)发生Michael加成, 得到β-碲代酯(腈), 产率较高.     

Microwave promoted oxazole synthesis: cyclocondensation cascade of oximes and acyl chlorides

Microwave irradiation promotes the rapid O,N-acylation-cyclodehydration cascade reaction of oximes and acid chlorides to give oxazoles.     

二碘化钐促进的二硫代氨基甲酸酯和硫代氨基甲酸酯的还原断裂反应

室温下SmI2-THF-HMPA-t-BuOH体系可顺利地将二硫代氨基甲酸酯还原断裂得到二硫醚和硫代甲酰胺; 同样条件下, 硫代氨基甲酸酯还原断裂得到二硫醚篅34The reductive cleavage of dithiocarbamic esters are promoted by the SmI2-HMPA-THF-t-BuOH System successfully to give disulfides and thiocarboxamides at room temperature in good yields; The reduction of thiocarbamic esters are also promoted by the same system to give disulfides and carboxamides.     

Microwave promoted methylation of plant polysaccharides

O-Methylation is of outstanding importance in structural polysaccharide chemistry. A novel method for the methylation of polysaccharides using microwave (MW) irradiation is described. Seed gum from Cyamopsis tetragonolobus (Guar) was fully methylated with dimethyl sulphate and sodium hydroxide using 100% microwave power for 4 min in 68% yield. The completely methylated seed gum thus obtained was hydrolyzed by 70% formic acid followed by 0.5N H₂SO₄ under full microwave power for 1.16 and 1.66 min, respectively. The partially methylated monosaccharides were separated and identified.     

Microwave promoted amination of 3-bromoisoxazoles

This Letter describes the amination of 3-bromoisoxazoles by a nucleophilic aromatic substitution reaction. We have found 3-bromoisoxazoles to be inert to substitution under thermal conditions, however, the employment of phosphazene bases under microwave irradiation facilitates the amination process and allows the corresponding 3-aminoisoxazoles to be isolated in moderate yield.     

Electrochemically promoted decarboxylative borylation of alkyl N-hydroxyphthalimide esters

An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.     

Electrochemically promoted decarboxylative borylation of alkyl N-hydroxyphthalimide esters

An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.     

Decarbonylation of thiol esters to give sulfides promoted by transition metal complexes

Thiol esters are converted into sulfides through decarbonylation promoted by catalytic amounts of Pd(0) compounds or stoichiometric amounts of Rh(I) compounds.     

Sodium cyanide‐promoted copper‐catalysed aerobic oxidative synthesis of esters from aldehydes

A simple and efficient copper‐catalysed procedure for oxidative esterification of aldehydes with alcohols and phenols mediated by sodium cyanide, using air as a clean oxidant, is described. A variety of aromatic aldehydes and structurally different alcohols and phenols reacted efficiently, and the product esters were obtained in good to excellent yields under normal atmospheric and solvent‐free conditions.     

Microwave irradiation assisted facile synthesis of new imidazole,pyrazine, and benzodiazocine derivatives using diaminomaleonitrile

Utilizing domestic microwave oven reactions of diaminomaleonitrile with various selected reagents, novel heterocycles such as dicyanopyrazine, 4,5‐dicyanoimidazole as well as dicyanobenzodiazocine derivatives were prepared. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:365–368, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20212     

铟促进的烯丙基硒醚的合成

烯丙基溴和炔丙基溴在铟促进下与二硒化合物反应，生成烯丙基和炔丙基硒醚。反应无需严格的无水无氧条件，烯丙基溴以α-位与二硒化合物反应，产率55%～91%。     

Photocatalytic synthesis of tetra-substituted furans promoted by carbon dioxide

We report a simple protocol for the transition metal-free, visible-light-driven conversion of 1,3-diketones to tetra-substituted furan skeleton compounds in carbon dioxide (CO₂) atmosphere under mild conditions. It was found that CO₂ could be incorporated at the diketone enolic OH position, which was key to enabling the cleavage of a C–O bond during the rearrangement of a cyclopropane intermediate. This method allows for the same-pot construction of two isomers of the high-value tetra-substituted furan scaffold. The synthetic scope and preliminary mechanistic investigations are presented.

A CO₂-promoted transition metal-free photocatalytic synthesis of tetra-substituted furan derivatives from 1,3-diketones as the only starting material.     

Reaction of imidazole with toluene-4-sulfonate salts of substituted phenyl N-methylpyridinium-4-carboxylate esters: special base catalysis by imidazole

The reaction of imidazole in aqueous solution with toluene-4-sulfonate salts of substituted phenyl N-methylpyridinium-4-carboxylate esters obeys the rate law: k(obs) - k(background) = k2[Im] + k3[Im]2 where [Im] is the imidazole concentration present as free base. The parameters k2 and k3 fit Br?nsted type free energy correlations against the pKa of the leaving phenol with betaLg values of -0.65 and -0.42 respectively. The imidazolysis is insensitive to catalysis by general bases and yet k3 for the 3-cyanophenyl ester possesses a deuterium oxide solvent isotope effect of 4.43 consistent with rate limiting proton transfer. A special catalytic function is proposed for decomposition of the tetrahedral addition intermediate (T+/-) via k3 whereby the catalytic imidazole interacts electrophilically with the leaving phenolate ion and removes a proton from the nitrogen in the rate limiting step with subsequent non-rate limiting ArO-C bond fission. This is consistent with the change in effective charge on the leaving oxygen in the transition structure of k3 which is more positive (-0.42) than that expected (-0.60) for the equilibrium formation of the zwitterion intermediate. The catalytic function at the leaving oxygen is likely to be an electrophilic role of the NH as a hydrogen bond donor. In the k2 step the deuterium oxide solvent isotope effect of 1.51 for the 3-cyanophenyl ester and the betaLg of -0.65 are consistent with rate limiting expulsion of the phenolate ion from the T+/- intermediate. The absence of general base catalysis of imidazolysis rules out the established mechanism for aminolysis of esters where T+/- is stabilised by a standard rate limiting proton transfer. The kinetically equivalent term for k3 where T- reacts with the imidazolium ion as an acid catalyst would require this step to be rate limiting and involve proton transfer not consistent with departure of the good aryl oxide leaving group.     

Tandem multi-step synthesis of C-carboxyazlactones promoted by N-heterocyclic carbenes

Cascade reaction sequences incorporating N-heterocyclic carbene-based organocatalysis have been developed that allow the direct preparation of a range of (+/-)-4-phenoxycarbonylazlactones in good isolated yields (66-84%) from the corresponding N-p-anisoyl amino acids.     

Microwave promoted synthesis of cycl[3.2.2]azines in water via a new three-component reaction

A microwave-promoted and base-catalyzed synthesis of cycl[3.2.2]azines is accomplished in water via a three-component reaction (3-CR) of 2-picoline, α-bromoacetophenone and alkyne. The extension of the methodology to the synthesis of steroidal and carbocyclic cycl[3.2.2]azine is also reported.