Cu(OTf)₂‐Mediated Cross‐Coupling of Nitriles and N‐Heterocycles with Arylboronic Acids to Generate Nitrilium and Pyridinium Products**

Abstract

Metal-catalyzed C-N cross-coupling generally forms C À Nb onds by reductive elimination from metal complexes bearing covalent C-and N-ligands.W eh ave identified aCu-mediated C-N cross-coupling that uses adative N-ligand in the bond-forming event, which,i nc ontrast to conventional methods,g enerates reactive cationic products. Mechanistic studies suggest the process operates via transmetalation of an aryl organoboron to aC u II complex bearing neutral N-ligands,s uch as nitriles or N-heterocycles.S ubsequent generation of ap utative Cu III complex enables the oxidative C-N coupling to take place,d elivering nitrilium intermediates and pyridinium products.The reaction is general for arange of N(sp) and N(sp 2)precursors and can be applied to drug synthesis and late-stage N-arylation, and the limitations in the methodology are mechanistically evidenced.

Cu-Catalyzed Tandem C–N and C–C Bond Formation Leading to 4(1H)-Quinolones: A Scaffold with Diverse Biological Properties from Totally New Raw Materials in a Single Step

“…To the best of our knowledge, there is no such strategy employed so far for constructing 2substituted-4 (1H)-quinolones. 17 To evaluate our idea, we first treated a mixture of (2acetylphenyl)boronic acid (10) [or its pinacolate ester (11a)] and benzonitrile (12a) at various conditions in the presence of different Cu reagents (Table 1). When a mixture of 10 and 12a was treated with CuBr 2 in the presence of a base (K 2 CO 3 , tBuOK, Cs 2 CO 3 , NaOH, pyridine, triethyl amine, etc.)…”

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

“…In fact, the use of CuSO4 with the cyano group lowered the yield (31% entry 12 in Table 1 used with CuSO4) which might be due to the coordination of the copper catalyst with the cyano group hindering the triazole formation. 34 The substrate containing 3,4,5-timethoxy (4f) substituent was afforded in a moderate 45% yield.…”

Gold-Catalyzed CN Cross-Coupling Reactions of Aryl Iodides with Alkyl Nitriles or Silver Cyanate

“…)cyclopropanecarboxamide (3j) [7] White solid, 60% (14.2 mg, petroleum ether / ethyl acetate = 2:1). [6] White solid, 54% (12.9 mg, petroleum ether / ethyl acetate = 2:1). [8] White solid, 40% (10.1 mg, petroleum ether / ethyl acetate = 2:1).…”

“…[8] White solid, 40% (10.1 mg, petroleum ether / ethyl acetate = 2:1). [6] White solid, 68% (19.5 mg, petroleum ether / ethyl acetate = 2:1). 1 H NMR (400 MHz, Chloroformd) δ 7.57 -7.46 (m, 6H), 7.44 -7.36 (m, 5H), 7.36 -7.27 (m, 4H), 3.73 (s, 2H).…”

“…Hz, 1H),6.48 (dd, J = 17.0, 10.2 Hz, 1H), 6.30 (dd, J = 17.0, 2.0 Hz, 1H), 5.79 (dd, J = 10.1, 2.0 Hz, 1H).13 C NMR (151 MHz, DMSO-d 6 ) δ 163.7, 140.1, 139.0, 135.6, 132.3, 129.4, 127.5, 127.5, 126.74, 120.18.…”