Divergent synthesis of unsymmetrical azobenzenes via Cu-catalyzed C–N coupling

Abstract

An efficient, one-pot, and cheap metal-catalyzed tandem Chan-Lam coupling/deprotection/oxidation reaction to access unsymmetrical azobenzenes is disclosed. In this protocol, phthaloyl is automatically fallen off under this basic catalytic system, without...

Decarbonylative/decarboxylative [4 + 2] annulation of phthalic anhydrides and cyclic iodoniums towards triphenylenes

“…Based on the above results and previous literature, 17–24 a possible reaction mechanism is proposed in Scheme 5. A six-membered acylpalladium carboxylate metallacycle Int-A is formed via oxidative addition (OA) of palladium to the C–O bond.…”

“…Considering that phthalic anhydrides are cheap, safe and widely accessible starting materials and they can form the same palladacycle as benzoic acids, 18 we envision that they can react with cyclic diaryliodoniums to produce triphenylenes. As part of our ongoing investigations on the domino reactions of hypervalent iodine( iii ) reagents, 19 herein, we disclose a palladium-catalyzed tandem decarbonylative and decarboxylative [4 + 2] annulation of phthalic anhydrides with cyclic iodoniums to obtain triphenylenes in a short time (1 h) (Scheme 1d).…”

Synthese von unsymmetrischen Azobenzolen durch palladiumkatalysierte Kreuzkupplung von siliciummaskierten Diazenylanionen und (Hetero)arylhalogeniden

“…Um die bevorzugte Heterodimerisierung zu erreichen, ist normalerweise ein großer Überschuss einer der beiden Kupplungspartner vonnöten. Diese Einschränkung wurde jüngst von Li und Mitarbeitern mit der Entwicklung einer Chan–Evans–Lam‐artigen oxidativen Kreuzkupplung von N ‐Arylphthalsäurehydraziden und Arylboronsäuren unter Kupferkatalyse in Angriff genommen (Schema 1, unten) [12] . Dieser elegante Lösungsansatz lieferte eine Unterklasse an Azobenzolen in moderaten bis guten Ausbeuten.…”

Cross-conjugation controls the stabilities and photophysical properties of heteroazoarene photoswitches

“…Azobenzene is the most widely studied photoswitch and has a well-documented synthesis via diazonium coupling reactions. Azobenzene has been synthesized using cross-coupling reactions, [1][2][3] nucleophilic aromatic substitution, 4 Bayer-Mills reactions, 5,6 and diazonium coupling. 7 The relatively small size of azobenzene, along with the significant chemical and structural changes resulting from isomerization, has enabled its use for the spatiotemporal control of proteins, lipids, neurotransmitters, neurons, and carbohydrates.…”