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。
Synthesis of Fluoroalkylated β-Aminophosphonates and Pyridines from Primary β-Enaminophosphonates
作者:Francisco Palacios、Ana M. Ochoa de Retana、Julen Oyarzabal、Sergio Pascual、Guillermo Fernández de Trocóniz
DOI:10.1021/jo8005667
日期:2008.6.1
and efficient stereoselective synthesis of fluorine containing β-aminophosphonates by reduction of β-enaminophosphonates is described. Reduction with sodium cyanborohydride in the presence of zinc chloride and the catalytic hydrogenation of β-enaminophosphonates gives β-aminophosphonates. β-Enaminophosphonates are also used as intermediates for the regioselective synthesis of fluoroalkyl-substituted pyridines
Preparation of Fluoroalkyl Imines, Amines, Enamines, Ketones, α-Amino Carbonyls, and α-Amino Acids from Primary Enamine Phosphonates
作者:Francisco Palacios、Ana María Ochoa de Retana、Sergio Pascual、Julen Oyarzabal
DOI:10.1021/jo048682m
日期:2004.12.1
A simple method for preparation of fluoroalkyl β-enaminophosphonates 1 from alkylphosphonates 2 and perfluoroalkyl nitriles 3 is reported. Olefination reaction of functionalized phosphates 1 with aldehydes gives α,β-unsaturated imines 5. Acid hydrolysis of these fluoroalkyl derivatives 5 affords α,β-unsaturated ketones 6, while their selectivereduction with hydrides leads to the formation of allylamines
A Weinreb amide approach to the synthesis of trifluoromethylketones
作者:DiAndra M. Rudzinski、Christopher B. Kelly、Nicholas E. Leadbeater
DOI:10.1039/c2cc35037h
日期:——
A novel route to access trifluoromethylketones (TFMKs) from Weinreb amides is reported. This represents the first documented case of the Ruppert–Prakash reagent (TMS–CF3) reacting in a constructive manner with an amide and enables synthesis of TMFKs without risk of over-trifluoromethylation.
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.