Acid-catalyzed cyclization reactions. IX. Formation of oxazolinium and thiazolinium cation from N-allyl and substituted N-allylamides, -urethans, -ureas, and -thioureas
chiral N-unsubstituted aziridines. It was found that the reaction was applicable to the asymmetric synthesis of 2-oxazolines from olefins when acyl chlorides were employed as activators. Complex 1 provided an effective asymmetric environment for trans-disubstituted styrenes in the reaction (up to 92% ee). This is the first example of a direct asymmetric synthesis of 2-oxazolines from olefins. Additional
Visible Light-Induced Regioselective Cycloaddition of Benzoyl Azides and Alkenes To Yield Oxazolines
作者:Peter Bellotti、Julien Brocus、Fatima El Orf、Mohamed Selkti、Burkhard König、Philippe Belmont、Etienne Brachet
DOI:10.1021/acs.joc.9b00568
日期:2019.5.17
regioselective synthesis of oxazolines in high yields. The mild photosensitized manifold leverages the intermolecular formation of oxazolines with a wide functional group tolerance on both benzoyl azides and alkenes partners. Mechanistic investigations suggest the sensitization of the azide moiety as the key activation step.
Copper-Catalyzed Aerobic Aliphatic C–H Oxygenation Directed by an Amidine Moiety
作者:Yi-Feng Wang、Hui Chen、Xu Zhu、Shunsuke Chiba
DOI:10.1021/ja305833a
日期:2012.7.25
A method for the oxygenation of tertiary C-H bonds of N-alkylamidines and N-(2-alkylaryl)amidines is described that utilizes the CuBr·SMe(2)/2,2'-bipyridine catalytic system under an O(2) atmosphere and provides dihydrooxazoles and 4H-1,3-benzoxazines. The oxygen atom is incorporated from atmospheric molecular oxygen during the present process.
The annulation reactions of benzoamidyl radicals with alkenes were realized under visible light irradiation with fac-Ir(ppy)3 as catalyst and N-aminopyridinium salts as benzoamidyl radical precursors. The reaction can deliver two distinct types of products: in the case of vinyl arenes, [3 + 2] annulation product dihydrooxazoles were yielded exclusively; when alkyl-substituted alkenes were used, on the
strategy is described here. Amide is used as the O- and N- source to probe for regiocontrol strategies. Notably, simple additives can be selectively introduced to achieve regiodivergent oxyamination processes for electronically activated alkenes while being regio-complementary for unactivated alkenes. Our preliminary data demonstrates that this regiocontrol strategy based on nucleophile can also be applied
本文描述了一种新型碘化物催化分子间氨氧化策略。酰胺用作 O 源和 N 源来探测区域控制策略。值得注意的是,可以选择性地引入简单的添加剂,以实现电子活化烯烃的区域发散的氧胺化过程,同时对未活化的烯烃进行区域互补。我们的初步数据表明,这种基于亲核试剂的区域控制策略也可以应用于使用手性高价碘催化的不对称过程。