The difluoroalkylation of unactivated benzo[d]isoxazoles with ethyl difluorobromoacetate by visible-light photoredox catalysis via direct and regioselective CH functionalization has been efficiently achieved under mild reaction conditions. The difluoroalkylated adducts could be readily converted to a variety of corresponding CF2-containing heterocycles, demonstrating the synthetic utility of the present
在温和的反应条件下,通过直接和区域选择性的C H官能团通过可见光光氧化还原催化有效地实现了未活化的苯并[ d ]异恶唑与二氟溴乙酸乙酯的二氟烷基化。二氟烷基化的加合物可以容易地转化成各种相应的含CF 2的杂环,证明了本方法的合成效用。
A novel method for the highly efficient synthesis of 1,2-benzisoxazoles under neutral conditions using the Ph3P/DDQ system
The use of Ph3P/DDQ offers a novel, neutral and highlyefficient method for the efficient conversion of 2-hydroxyaryl aldoximes and ketoximes to 1,2-benzisoxazoles in excellent yields at room temperature.
Ph 3 P / DDQ的使用提供了一种新颖,中性和高效的方法,可在室温下以优异的收率将2-羟基芳基醛肟和酮肟有效转化为1,2-苯并恶唑。
A new protocol for visible-light-induced C–H trifluoromethylation at C-4position of 1,2-benzoxazoles has been disclosed with Togni reagent II at room temperature in the presence of fac-Ir(ppy)3. This approach features simple operation, high efficiency, and specific selectivity.
Triflic Anhydride: A Mild Reagent for Highly Efficient Synthesis of 1,2-Benzisoxazoles, Isoxazolo, and Isothiazolo Quinolines Without Additive or Base
作者:Rajesh G. Kalkhambkar、H. Yuvaraj
DOI:10.1080/00397911.2013.821617
日期:2014.2.16
The synthetic utility of trifluoromethanesulphonic anhydride (triflic anhydride, TA) without additive or base for the high-yielding synthesis of a wide variety of 1,2-benzisoxazoles from 2-hydroxyaryl aldoximes and ketoximes under mild conditions has been carried out for the first time. As a continuation of our study, syntheses of isoxazolo and isothiazolo quinolones have also been demonstrated using triflic anhydride under similar conditions. This method is simple and has benefits from the easy way to isolate the products in excellent yields. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resource(s): Full experimental and spectral details.]
ELKASABY, M. A.;SALEM, M. A. I., INDIAN J. CHEM., 1980, 19, N 7, 571-575