Ruthenium‐Catalyzed Direct Transformation of Alkenyl Oximes to 5‐Cyanated Isoxazolines: A Cascade Approach Based on Non‐Stabilized Radical Intermediate

• Published in: European journal of organic chemistry Vol. 2018; no. 11; pp. 1342 - 1346
• Main Authors: Wang, Dan‐Jun, Chen, Bei‐Yi, Wang, Yi‐Qi, Zhang, Xiao‐Wei
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 22.03.2018; Wiley Subscription Services, Inc
• Subjects: Alkenes; Cascade reaction; Chemistry; Chemistry, Organic; Cyanation; Cyanides; Functional groups; Initiators; Isoxazoline; Nitrogen; Oximes; Physical Sciences; Radical cyclization; Reagents; Ruthenium; Science & Technology; Cascade reaction; Oximes; Cyanation; HIGHLY EFFICIENT; UNACTIVATED ALKENES; Radical cyclization; NITRILES; C-C BOND; ARYL HALIDES; PRIMARY AMIDES; PALLADIUM(II)-CATALYZED DIRECT CONVERSION; DIRECT OXIDATIVE CONVERSION; METHYL ARENES; Isoxazoline
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201701651

A ruthenium‐catalyzed ammoxidation of alkenyl oximes under mild and neutural condtions is described. In this method, tert‐butyl nitrite plays a dual role, acting as an oxidant as well as a nitrogen source. This reaction avoids using any toxic radical initiators or cyanide reagents. This convenient and practical method offers an easy access to 5‐cyanated isoxazolines in good to high yields, and shows good functional group tolerance and high efficiency. It is rather remarkable that this new reaction provides a strategically distinct approach based on non‐stabilized radical intermediate and constructs C–O and C≡N triple bonds in a single‐step. Moreover, the difunctionalization of unactivated olefins bearing oximes has been realized. A convenient method offers an easy access to 5‐cyanated isoxazolines in good to high yields and shows good functional group tolerance and high efficiency. In this protocol, tert‐butyl nitrte plays a dual role, acting as an oxidant as well as a nitrogen source. Remarkably, this new reaction avoids using any toxic radical initiator or cyanide reagents and constructs C–O and C≡N triple bonds in a single‐step.