From the direct C-H arylation of azoles to the synthesis of chiral helical phosphorus ligands: a journey through the eclectic world of the organometallic catalysis

Regio and stereoselective synthesis using organometallic catalysts is currently one of the most active areas of research in organic chemistry. A rapid progress in the study of organometallic and coordination compounds has led to the development and successful industrial application of a number of catalytic processes based on use of these compounds as catalysts. The major advantage of organometallic catalysis is selectivity, and the ability to produce pure products in high yield. Two different topics in the field of the transition metal complex catalyzed regio and stereoselective organic transformations will be addressed. The first topic will concern the regioselective palladium- and/or copper-mediated direct C-H arylation of π-electron-rich heteroarenes with (hetero)aryl halides. Recently, the transition metal-catalyzed direct arylation of heteroaromatic compounds has emerged as an attractive strategy for the effective construction of aryl–aryl bonds which, unlike the traditional metal-catalyzed cross-coupling strategies involving preformed organometallic reagents, enables direct elaboration of heterocyclic cores without the use of preactivated coupling partners.1 In the second issue, the study of a new class of thiahelicene-based phosphanes as potential innovative chiral ligands in asymmetric organometallic catalysis will be discussed, especially in the homogenous rhodium(I)-catalyzed hydrogenation reactions, and gold(I)-catalyzed cycloisomerizations. Although helicenes displaying phosphorus functions represent promising scaffolds for applications in enantioselective organometallic catalysis,2 to date their uses in this field is still in its infancy, especially in terms of number of compounds as well as structural diversity.