Copper-Mediated Multiple C–H Functionalization of Aromatic N-Heterocycles: Bromoamination of Indoles and Pyrroles

Abstract

A copper-mediated bromoamination of aromatic N-heterocycles has been achieved using oxime esters as the N-reagents under mild conditions (ca. 70 °C). The reaction with N-alkyl indoles proceeds regioselectively to produce the 2-amino-3-bromo indole derivatives as confirmed by X-ray crystallographic analysis of the bromoaminated product, 3aa-Br. With N-methylpyrrole both the monobromoaminated and dibromoaminated products were produced by this method.

Transition Metal‐Catalyzed Reactions Involving Oximes

“…In 2012, Nicholas et al. developed a copper‐mediated regioselective bromoamination of indoles with oxime esters (Scheme ) . A series of oxime esters reacted with substituted indoles to afford 2‐amino‐3‐bromoindole derivatives 341 and bromination by‐product indole 342 (Scheme ).…”

Metal Carbides as Alternative Electrocatalyst Supports

“…11 Various oxime esters and CuX salts participate in the C-H functionalization reaction to produce the respective haloamine adducts in moderate yield (Scheme 8). Yields were moderate due to formation of a competing indole mono-halogenation product, presumably formed from reaction of the indole with CuX 2 .…”

Copper‐Catalyzed C(sp3)−H/C(sp3)−H Cross‐Dehydrogenative Coupling with Internal Oxidants: Synthesis of 2‐Trifluoromethyl‐Substituted Dihydropyrrol‐2‐ols

“…Theaddition of CsOPiv is likely to favor the conversion of 2a into its enol form 2a-E.Onthe basis of these experimental results as well as previous work, [6][7][8]17] we tentatively formulated the reaction mechanism illustrated in Scheme 6. Oxidative addition of the N À Obond of 1a to copper(I) gives rise to organocopper(III) intermediate A.…”

“…Furthermore, different inorganic and organic bases were used as additives (entries [13][14][15][16][17][18][19][20]. Other metal catalysts such as Pd(OAc) 2 ,Rh 2 (OAc) 4 ,orFeCl 3 did not show any catalytic activity,and the desired product was not detected in the absence of copper catalyst (entry 12).…”