[RhIII(Cp*)]‐Catalyzed ortho‐Selective Direct C(sp2)H Bond Amidation/Amination of Benzoic Acids by N‐Chlorocarbamates and N‐Chloromorpholines. A Versatile Synthesis of Functionalized Anthranilic Acids1. Issue 15 (5th March 2014)

• Record Type: Journal Article
• Authors: Ng, Fo‐Ning; Zhou, Zhongyuan; Yu, Wing‐Yiu
• Is Part Of: Chemistry. Volume 20:Issue 15(2014)
• Page Start: 4474
• Page End: 4480
• Publication Date: 2014-03-05
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201304855
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A Rh^III‐catalyzed direct <italic>ortho</italic>‐CH amidation/amination of benzoic acids with <italic>N</italic>‐chlorocarbamates/<italic>N</italic>‐chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent <italic>ortho</italic>‐selectivity and functional‐group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO₂Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[<italic>h</italic>]quinoline with a silver salt of <italic>N</italic>‐chlorocarbamate afforded an amido–rhodium(III) complex, which was isolated and structurally characterized by X‐ray crystallography. This finding confirmed that the CN bond formation results from the cross‐coupling of <italic>N</italic>‐chlorocarbamate with the aryl–rhodium(III) complex. Yet, the mechanistic details regarding the CN bond formation remain unclear; pathways involving 1, 2‐aryl migration and rhodium(V)– nitrene are plausible.</p> </abstract>