Direct Cu‐Catalyzed Allylic Acetoxylation of Δ5‐Steroids at 7‐Position

The efficiency and selectivity of Cu‐catalyzed allylic acetoxylation of alkene in different solvent systems is improved by the presence of different metallic salts in the reaction medium. The methodology is particularly well employed for the direct allylic acetoxylation of Δ⁵‐steroids at 7‐position, for which the resulting acetoxylated product obtained was exclusively α‐isomer. Excellent yield was achieved (up to 90%) under optimized conditions, while significantly reducing the costs and environmental hazards and increasing the yield as compared to the other previously reported methods.     

A Convenient Method for Chlorination in Allylic Position

A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%-5% active chlorine) and an acid as chlorination reagent in a diphase system.The method has the advantage of cheap reagents, mild reaction conditions and good yields. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in laboratories.     

烯丙位氧化的几种方法

综述了近年来烯丙位氧化的研究进展，详细讨论了过渡金属及其络合物、硒化 合物在烯丙位氧化中的应用，并简述了丁基锂方法、固相催化方法、生物氧化方法 和次氯酸钠氧化方法在烯丙位氧化中的应用．     

Allylic oxidation of cyclohexene over silica immobilized iron tetrasulfophthalocyanine

Iron tetrasulfophthalocyanine was immobilized on silica (FePcS-SiO₂) and its activity examined on the allylic oxidation of cyclohexene using TBHP as oxidant. Under our reaction conditions, attack of the activated C-H bond was preferred instead of the epoxidation of CC bond, yielding 2-cyclohexen-1-one as the main product. μ-Oxo dimeric (d-FePcS) appears to be the active species for this reaction.     

Simple,Copper(I)-Catalyzed Oxidation of Benzylic/Allylic Alcohols to Carbonyl Compounds: Synthesis of Functionalized Cinnamates in One Pot

An environmentally benign [Cu(I)]-catalyzed oxidation of activated (benzylic/allylic) alcohols to the corresponding carbonyl compounds is presented. Interestingly, the reaction was also compatible with benzylic alcohols containing ortho-bromo substituents on the aromatic ring without competing with the expected intermolecular Buchwald coupling. Significantly, the catalytic system enables the synthesis of cinnamate-esters in a sequential domino one-pot fashion via oxidation followed by Wittig–Horner protocol.     

C2H4的微波场助气相光催化氧化

用溶胶-凝胶法制备了多孔性TiO     

五氧化二钒催化环己烯烯丙位氧化

 研究了以五氧化二钒为催化剂,以过氧化氢水溶液为氧源氧化环己烯. 考察了溶剂种类、溶剂用量、催化剂用量和反应温度等因素对催化剂性能的影响. 结果表明,常温下环己烯在此催化体系中主要发生烯丙位氧化反应生成环己烯酮. 溶剂的种类对催化活性和烯丙位酮式氧化的选择性具有较大的影响,丙酮是该反应的合适溶剂. 在丙酮与环己烯的体积比为4, 五氧化二钒与环己烯的质量比为1∶40, 过氧化氢与环己烯的摩尔比为3和反应温度为20 ℃的条件下,反应24 h后的环己烯转化率可达60%以上,环己烯酮选择性可达85%. 催化反应过程中丙酮可能与过氧化氢作用生成过氧化酮,从而进行氧转移,催化剂则经过V5+/V4+物种的循环使环己烯氧化成为环己烯酮等产物.     

Regioselective Isomerisation of Highly Substituted 1-Methylenecyclohexenepoxides to the Corresponding Allylic Alcohols. Influence of the Base and of the Protecting Groups

Summary. Highly substituted 1-methylenecyclohexenepoxides 3, useful building blocks for a projected synthesis of wailupemycin A (1), were synthesized from (R)-carvone in eight synthetic steps in 23–40% overall yield. The regioselectivity of the subsequent isomerisation to the corresponding allylic alcohols was shown to depend on the basicity of the reagent and on the bulkiness of the protecting groups existing in 3. With diethylaluminum 2,2,6,6-tetramethylpiperidid (DATMP), secondary allylic alcohols 5 were formed exclusively. With strong bases such as a mixture of lithium di-iso-propylamide and potassium tert-butoxide (LIDAKOR), the tertiary allylic alcohol 6 was obtained as predominant product.To whom inquiries about the X-ray analysis should be addressed     

Microwave-assisted oxidation of alcohols using Magtrieve™

Primary and secondary alcohols can be selectively oxidized under microwave irradiation into the corresponding aldehydes and ketones within 5-30 min using commercially available and magnetically retrievable Magtrieve™.     

Direct Synthesis of Allylic Thioethers Under Greener Conditions: A Solvent- and Catalyst-Free Approach

We present herein a new catalyst-free and solvent-free approach for the synthesis of allylic thioethers directly from allylic alcohols and thiols. The methodology allows the synthesis of different allylic thioethers in good to excellent yields under microwave irradiation. Theoretical calculations for the allylic carbocation helped to explain the regioselectivity observed when nonsymmetric substrates are used in the reaction.     

紫罗兰酮的烯丙位氧化制备氧代紫罗兰酮的研究进展

综述了α-和β-紫罗兰酮经烯丙位氧化制备氧代紫罗兰酮的研究进展,依据不同的氧化剂分为五大类,详细地分析了各种方法的特点,指出了今后的发展趋势。     

STUDY ON BclI/St14 RFLPs IN CHINESE FOR DNA DIAGNOSIS FOR HEMOPHILIA A

The BclI polymorphism within DXS52 (St14) was reported. It was composed of 4 allelic fragments 4.0 kb, 3.3 kb, 3.0 kb and 2.3 kb, The frequency of these fragments were 0.09, 0.12, 0.44 and 0.35 respectively in the Chinese. The polymorphism provided the PIC of 0.66. DNA analysis of families, with hemophilia A showed that the confidence of the RFLPs was the same as the TaqI/St14 RFLPs and for carrier detection the former is much better than that of the TaqI/St14 RFLPs.     

Enantioselective Allylic Oxidation of Olefins Using Chiral Quinolinyl‐oxazoline Copper Complex Catalysts

Copper complexes of chiral quinolinyl‐oxazoline have been studied as the catalysts for enantioselective allylic oxidation of cycloalkenes with tert‐butyl perbenzoate. Using 5 mol% of these chiral catalysts, optical active allylic benzoates were obtained in moderate enantiomeric excesses. CuOTf prepared in situ, CuClO₄ and CuPF₆ were found to be good precatalysts in acetone.     

Iodine Catalyzed Microwave-Assisted Synthesis of 14-Aryl（Alkyl）-14H-dibenzo[a,j]xanthenes

A straightforward and effective procedure for the synthesis of 14-aryl（alkyl）-14H-dibenzo[aj]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the corresponding xanthenes in good yields.     

锡促进的烯丙基硒醚和烯丙基硫醚的合成

在金属锡促进下，烯丙基溴与二硒醚或二硫醚反应，生成烯丙基硒醚或烯丙基硫醚 。     

Photoassisted Catalytic Oxidation of Carbon Monoxide at Room Temperature

Summary. The thermal and photoassisted catalytic oxidation of CO at metal oxide supported RuO₂·xH₂O was studied at room temperature. Contrary to neat RuO₂·xH₂O the supported catalysts suffer from fast deactivation attributed to strong adsorption of the reaction product carbon dioxide. The latter can be efficiently removed from the catalyst surface at elevated temperatures. In some cases, i.e. for catalysts supported with selected n-type semiconductors (TiO₂, SnO₂, WO₃), efficient CO₂ desorption and good, constant catalytic activity was observed upon visible light irradiation. Under such conditions the CO to CO₂ conversion observed for RuO₂·xH₂O/TiO₂ was nearly as good and stable as for the unsupported catalyst. It is suggested that light absorption promotes carbon dioxide desorption through positive charging of the catalyst surface.     

微波辐射合成5,12-二氢-5,7,12,14-四氮杂并五苯

以微波辐射辅助的方法合成5,12-二氢-5,7,12,14-四氮杂并五苯,实验证明微波辐射能促进2,3-二羟基吩嗪和邻苯二胺反应.经正交试验分析,确定微波辐射反应最佳条件如下:2,3-二羟基吩嗪和邻苯二胺摩尔比为1:6;反应时间为150s;2,3-二羟基吩嗪与乙酸量之比为1∶1(mol/mL).经1H NMR、MS、熔...