Convenient One-Pot Synthesis of 2,5-Disubstituted Oxazoles via a Catalytic Oxidative Dehydrogenation of F<sub>3</sub>CSO<sub>3</sub>H·SiO<sub>2</sub>-DDQ/CuCl<sub>2</sub>/LiCl
作者:Shizhen Yuan、Zhen Li、Ling Xu
DOI:10.1002/jhet.1637
日期:2013.11
A facile one‐potsynthesis of 2,5‐disubstitutedoxazoles was developed via cyclization of aldoximes and phenylacetylene then dehydrogenation oxidation. 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone was studied for the selective oxidation of oxazolines using Cu2+/Li+ as catalyst and O2 as indirect oxidant. The reaction results showed that this catalyst system can effectively catalyze the oxidation of oxazolines
通过醛肟和苯乙炔的环化然后脱氢氧化制得了一种简便的一锅合成2,5-二取代的恶唑。以Cu 2+ / Li +为催化剂,O 2为间接氧化剂,研究了2,3-二氯-5,6-二氰基-1,4-苯醌对氧化唑啉的选择性氧化。反应结果表明,该催化剂体系可有效催化恶唑啉氧化为相应的恶唑。因此,通过2,3-二氯-5,6-二氰基-1,4-苯醌/ CuCl 2 / LiCl / O 2的催化氧化,很容易以高收率合成各种多取代的恶唑。
Synthesis of 2,5-disubstituted oxazoles <i>via</i> cobalt(<scp>iii</scp>)-catalyzed cross-coupling of <i>N</i>-pivaloyloxyamides and alkynes
An efficient synthesis of 2,5-disubstitutedoxazolesvia Co(III) catalysis is described herein. The synthesis is achieved under mild conditions through [3+2] cycloaddition of N-pivaloyloxyamides and alkynes. The reaction operates through an internal oxidation pathway and features a very broad substrate scope. The one-step synthesis of natural products such as texamine and balsoxin has been demonstrated
A facile type of one-pot, transition-metal-free domino process was developed for the synthesis of oxazoles. Thus, a variety of polysubstituted oxazoles were easily synthesized via t-BuOOH/I2-mediated dominooxidativecyclization from readily available starting materials under mild conditions.
开发了一种简便的单罐,无过渡金属的多米诺骨牌工艺,用于合成恶唑。因此,通过t- BuOOH / I 2介导的多米诺氧化环化反应可以容易地在温和条件下从容易获得的起始原料合成多种多取代的恶唑。
Metal-free iodine(<scp>iii</scp>)-promoted synthesis of 2,5-diaryloxazoles
A nonmetal-catalyzed oxidative cyclization to achieve 2,5-disubstituted oxazoles from inexpensive and readily available substituted chalcone, (diacetoxyiodo)benzene (PIDA) and ammonium acetate (NH4OAc) at room temperature is described. The reaction forms a variety of 2,5-diaryloxazoles in good to excellent yields with broad substrate scope under mild conditions without the requirement of ligands and
Iodine catalyzed synthesis of 2,5-substituted oxazoles from N-arylethylamides through intramolecular C(sp3)–H functionalization under metal-free conditions is described.