Fluorine Effects on Group Migration via a Rhodium(V) Nitrenoid Intermediate. Issue 47 (9th October 2017)

• Record Type: Journal Article
• Authors: Wang, Cheng‐Qiang; Zhang, Yu; Feng, Chao
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 47(2017)
• Page Start: 14918
• Page End: 14922
• Publication Date: 2017-10-09
• Subjects: C−H activation -- fluorine effects -- hydroarylation -- Lossen rearrangement -- rhodium; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201708505
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: An unprecedented rhodium(III)‐catalyzed hydroarylation of α, α‐difluoromethylene alkynes with N ‐pivaloxyl aroylamides through sequential C−H activation and aryl migration is detailed herein. A large array of α, α‐difluoromethylene alkynes and N ‐pivaloxyl aryl amides were amenable to this transformation, thus providing a novel synthetic protocol for the construction of difluorinated 2‐alkenyl aniline derivatives in high yields and with excellent regioselectivity. Notably, unique fluorine effects were found to underlie the thus unconventional reaction manifold. Abstract : Exploring new avenues : Rhodium(III)‐catalyzed hydroarylation of α, α‐difluoromethylene alkynes with N ‐pivaloyloxy aryl amides enabled the efficient regiospecific synthesis of difluorinated 2‐alkenyl aniline derivatives (see scheme). The fluorine substituents in the alkyne substrates diverted the course of the reaction from the conventional annulation pathway to promote the hydroarylation process involving Lossen rearrangement.