2-Pyridyl Sulfoxide: A Versatile and Removable Directing Group for the PdII-Catalyzed Direct CH Olefination of Arenes

Abstract:

Removable and versatile: The 2-pyridylsulfinyl group has proved to be an efficient directing group in the Pd^II-catalyzed aryl ortho CH olefination. This catalyst system enables the sequential double olefination to give asymmetrically di-ortho-functionalized arenes. The sulfinyl directing group can be easily cleaved, providing access to 1,3-disubstituted arenes, or transformed into a thiol group.


DOI: 10.1002/chem.201003633

Controlling Site Selectivity in Pd-Catalyzed Oxidative Cross-Coupling Reactions

This paper presents a detailed investigation of the factors controlling site selectivity in the Pd-mediated oxidative coupling of 1,3-disubstituted and 1,2,3-trisubstituted arenes (aryl−H) with cyclometalating substrates (LC−H). The influence of both the concentration and the steric/electronic properties of the quinone promoter are studied in detail. In addition, the effect of steric/electronic modulation of the carboxylate ligand is discussed. Finally, we demonstrate that substitution of the carboxylate for a carbonate X-type ligand leads to a complete reversal in site selectivity for many arene substrates. The origins of these trends in site selectivity are discussed in the context of the mechanism of Pd-catalyzed oxidative cross-coupling.


http://pubs.acs.org/doi/abs/10.1021/ja1097918

Base-Mediated Intermolecular sp2 C−H Bond Arylation via Benzyne Intermediates

Abstract:

A transition-metal-free method for arylation of heterocycle and arene carbon−hydrogen bonds by aryl chlorides and fluorides has been developed. The reactions proceed via aryne intermediates and are highly regioselective with respect to the C−H bond coupling component.

Rh(NHC)-Catalyzed Direct and Selective Arylation of Quinolines at the 8-Position

Abstract:

A new catalytic protocol for the regioselective direct arylation of quinoline derivatives at the 8-position has been developed. The reaction is catalyzed by a Rh(NHC) system, and the choice of the NHC ligand was most important for achieving high reactivity and selectivity.

http://pubs.acs.org/doi/abs/10.1021/ja111670s

Iridium-catalysed direct C–C coupling of methanol and allenes

J Moran et al, Nat Chem, 2011, DOI: 10.1038/nchem.1001