Chan-Lam coupling

The Chan-Lam Coupling may be conducted at room temperature in air, which gives it a certain advantage over the Buchwald-Hartwig Cross Coupling. 

Scheme 5.4 Chan-Lam coupling reactions and a simplified catalytic cycle.

Copper has also found wide use however, it has generally only been found to be applicable to heteroatom-carbon coupling reactions when employing boronic acids as coupling partners, now known as the Chan-Lam coupling. ... 

Type of reaction C-N bond formation Reaction conditions Methanol, room temperature Synthetic strategy Chan-Lam coupling forming C-N bond Catalyst Cu(I)Cl/air... 

Keywords Aryl/heteroaryl boronic acids, sulfonyl azides, Cu(I)Cl, air, methanol, room temperature, Chan-Lam coupling, N-aryl/heteroaryl sulfonamides... 

Moon, S.-Y., Nam, J., Rathwell, K., and Kim, W.-S. (2014). Copper-catalyzed Chan-Lam coupling between sulfonyl azides and boronic acids at room temperature. Org. Lett., 16, 338-341. 

Finally, C—N bond formation has been also accomplished through aerobic oxidative amination of arylboronic acids (Evans-Chan-Lam coupling) under poly-NHC-copper(II) catalysis. In particular, azoles and aromatic amines were successfully coupled with arylboronic acid using catalyst 73, with catalytic efficiencies comparable to those of other previously reported copper(II)-based catalytic systems for this reaction. 

Arylation of a wide range of NH/OH/SH substrates by oxidative cross-coupling with boronic acids in the presence of catalytic cupric acetate and either triethyl-amine or pyridine at room temperature in air. The reaction works for amides, amines, anilines, azides, hydantoins, hydrazines, imides, imines, nitroso, pyrazi-nones, pyridones, purines, pyrimidines, sulfonamides, sulfinates, sulfoximines, ureas, alcohols, phenols, and thiols. It is also the mildest method for NIO-vinylation. The boronic acids can be replaced with siloxanes or starmanes. The mild condition of this reaction is an advantage over Buchwald-Hartwig s Pd-catalyzed cross-coupling. The Chan-Lam C-X bond cross-coupling reaction is complementary to Suzuki-Miyaura s C-C bond cross-coupling reaction. 

A Chan-Lam-Evans coupling has also been designed as a new method to access O-vinyl-iV-arylhydroxylamines under mild conditions that avoid the use of strong bases as described previously for the Bartoli-indole synthesis and related preparations of oxindoles (see Section 14.2.3). Anderson and coworkers have shown that treatment of iV-arylhydroxamic acids with vinylboronic acids leads directly to the synthesis of a-(o-anilido)ketones such as 90 f Scheme... 

Reactions of Aryl Boronic Acids with Amines and Aicohols (Chan-Evans-Lam Couplings)... 

Use of Arylboronic Acids and Derivatives Instead of Arylhalides Chan-Lam-Evans Coupling and Other Variants... 

N, O and S arylation have become very well developed catalytic processes over the last 15 years, with the powerful methods of Buchwald-Hartwig, Chan-Lam-Evans and the Migita coupling protocol. 

In Chapter 2, which in many ways is an extension of Chapter 1 and much connected to Chapter 4, the authors present a general overview of the most common X-H (X = N, O, S) arylation methods, which have suffered an explosion of developments over the last 10 years or so. Methods, such as Buchwald-Hartwig and Chan-Lam-Evans coupling, are at the forefront of this chapter. This is a very extensive chapter. 

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