N‐(4‐Thiazolylmethyl)Morpholine N‐Oxide as N,O‐Bidentate Ligand for Copper‐Catalyzed Ullmann‐Type N‐Arylation of Azoles/Amines with Aryl Halides

Abstract

An effective and practical protocol for the CuIcatalyzed Ullmann-type N-arylation of azoles/amines with aryl halides is reported. The key strategy is the employment of CH 2 linker N,O-bidentate ligands, especially N-(4-thiazolylmethyl)morpholine N-oxide, as superior supporting ligands. The highly efficient CÀ N coupling reactions between various azoles/amines and aryl halides bearing different functional groups can be achieved under CuI/N-(4-thiazolylmethyl) morpholine N-oxide catalytic system, affording a variety of Narylated products. The use of cheap copper(I) salt and readily available N,O-bidentate ligands make this procedure more attractive for synthesis of valuable functionalized nitrogencontaining heterocyclic compounds.[a] Dr. under vacuum. Purification of the crude products was performed by flash column chromatography on silica gel (ethyl acetate/ petroleum ether = 1/12) to afford the desired product 7.

Palladium Complexes with N,O‐Bidentate Ligands Based on N‐Oxide Units from Cyclic Secondary Amines: Synthesis and Catalytic Application in Mizoroki‐Heck Reaction

“…[ 22 ] To our delight, these N,O‐bidentate ligands bearing N ‐oxide units also exhibited higher activity than commercially available N,N‐bidentate ligands such as 2,2’‐bipyridine or 1, 10‐phenanthroline in copper(I)‐catalyzed Ullmann‐type coupling of aryl halides with different amines/azoles. [ 23 ] Encouraged by these work, we speculate that these N,O‐bidentate ligands could be used for controllable synthesis of corresponding palladium(II) complexes, which could further be utilized as catalysts for C—C cross‐coupling reactions. Considering our continuous interest in metal‐catalyzed formation of chemical bonds, [ 24 ] we herein report the synthesis of four palladium complexes with N,O‐bidentate ligands based on N ‐oxides units from cyclic secondary amines and their catalytic properties in Mizoroki‐Heck reaction of aryl bromides with electron‐deficient olefins.…”

Synthesis and Optical Properties of Polyaryl 2‐(Pyridin‐2‐yl)phenol‐Based Four‐Coordinate Organoboron Complexes

“…2‐(Pyridin‐2‐yl)phenol framework represents a class of important N , O ‐bidentate ligand, which can react with boron trifluoride ether to provide N , O ‐difluoroboron complexes. [ 5 ] Traditionally, the preparation of these 2‐(pyridin‐2‐yl)phenol‐based organoboron complexes requires multi‐step sequence transformation (Suzuki coupling, deprotection, and coordination). [ 6‐7 ] Recently, Glorius reported a C—H activation based copper‐catalyzed one‐ shot synthesis of N,O ‐bidentate organic difluoroboron complexes from 2‐phenylpyridine derivatives (Scheme 1b).…”

Three copper(II) complexes derived from 2‐methylquinoline and cyclic secondary amines: Synthesis and catalytic application in C—N bond forming reactions

“…[ 33 ] The designed N , O ‐bidentate ligands also displayed their greater superiority than commercial available N , N ‐bidentate ligands (such as 2,2′‐bipyridine or 1,10‐phenanthroline) in copper(I)‐catalyzed Ullmann‐type coupling reaction between aryl halides and nitrogen‐containing substrates. [ 34 ] In order to further investigate the relation between the structure of N ‐oxide ligands and catalytic activity of formed copper complexes, we have synthesized three N , O ‐bidentate ligands derived from 2‐methylquinoline and cyclic secondary amines and prepared the corresponding copper complexes. The catalytic performance of these easily available copper complexes in Chan–Lam reaction of arylboronic acids with 1 H ‐imidazole derivatives was also discussed.…”