An efficient route to 3-trifluoromethylpyrazole via cyclization/1,5-H shift and its applications in the synthesis of bioactive compounds
摘要:
A methodology for regioselective synthesis of 3-trifluoromethylpyrazole from the reaction of trifluoromethyl alkenone and tosylhydrazone has been developed. The reaction was proposed to proceed through a tandem cyclization and 1,5-H shift reaction, which can be applied to the synthesis of bioactive compounds like Celecoxib, Mavacoxib, and SC-560. (C) 2015 Elsevier Ltd. All rights reserved.
methodologies and occurs through a trifluoroacyl radical mechanism promoted by a photocatalyst, which triggers a C−O bond fragmentation. Mechanistic studies (kineticisotopeeffects, spectroelectrochemistry, optical spectroscopy, theoretical investigations) highlight the evidence of a fleeting CF3CO radical under photoredox conditions. The trifluoroacyl radical can be stabilized under CO atmosphere, delivering
我们报告了一种温和且操作简单的烯烃三氟酰化策略,该策略利用三氟乙酸酐作为低成本且易于获得的试剂。这种光介导的过程与传统方法有着根本的不同,它通过由光催化剂促进的三氟酰基自由基机制发生,从而触发 CO 键断裂。机理研究(动力学同位素效应、光谱电化学、光谱学、理论研究)突出了转瞬即逝的 CF 3的证据光氧化还原条件下的 CO 自由基。三氟酰基自由基可以在 CO 气氛下稳定,提供具有更高化学效率的三氟乙酰化产物。此外,该方法可以通过简单地改变反应参数变成三氟甲基化协议。除了简单的烯烃外,该方法还允许小分子药物和常见药效团的化学和区域选择性功能化。
Highly enantioselective copper(<scp>i</scp>)-catalyzed conjugate addition of 1,3-diynes to α,β-unsaturated trifluoromethyl ketones
作者:Amparo Sanz-Marco、Gonzalo Blay、M. Carmen Muñoz、José R. Pedro
DOI:10.1039/c5cc01676b
日期:——
The conjugate diynylation of [small alpha],[small beta]-unsaturated trifluoromethyl ketones is carried out in the presence of a low catalytic load (2.5 mol %) of a copper(I)-MeOBIPHEP complex, triethylamine and a terminal 1,3-diyne....
The asymmetricepoxidation of electron‐deficient olefins has been achieved using inexpensive and readily available prolinols as catalysts with good to excellent yields and enantioselectivities. The utility of the resulting chiral epoxides was illustrated by elaboration to several synthetically useful compounds featuring a concise synthesis of (−)‐(5R,6S)‐balasubramide.
An enantioselective nucleophilic addition of α,β-unsaturated trifluoromethylketones catalyzed by l-proline derivatives
作者:Dehui Zhang、Chengye Yuan
DOI:10.1016/j.tet.2007.12.035
日期:2008.3
unexpected enantioselective 1,2-aldol reaction of acetone with α,β-unsaturated trifluoromethylketone catalyzed by l-proline derivative was described. The absolute configuration of the resulting chiral product was assigned based on a single crystal X-ray diffraction analysis. Structure–reactivity study of this organocatalytic system was briefly discussed. A reaction mechanism was tentatively postulated
A novel N,N-dibenzyl diaminomethylenemalononitrile organocatalyst efficiently promotes asymmetric Henry reactions of trifluoromethyl enones with nitromethane, affording the corresponding highly functionalized products in high yields with excellent enantioselectivities (up to 90% ee).