Experimental and Computational Studies on the Directing Ability of Chalcogenoethers in Palladium‐Catalyzed Atroposelective C−H Olefination and Allylation

Abstract

We present herein our experimental and DFT computational studies on the directing ability of chalcogenoether motifs in Pd-catalyzed atroposelective CÀ H functionalization. The thioether motif was found to be a superior directing group compared to the corresponding ether and selenoether in terms of reactivity and enantiocontrol. Remarkably, DFT calculation provided a predictive model for the optimization of reaction conditions and the interpretation of the origin of enantioselectivity. Both Pd-catalyzed enantioselective CÀ H olefination and allylation reactions were successfully developed using chiral phosphoric acids as efficient ligands, providing a broad range of axially chiral biaryls in good yields with excellent enantioselectivities. The highly enantio-and diastereoselective construction of polyaryls bearing multiple stereogenic axes, gram-scale reaction and various chemical transformations make this protocol more attractive and significant.

Ruthenium(II)-Catalyzed S(II)-Directed Aromatic C–H Allylation with Vinylaziridines

“…We wish to report a stereospecific synthesis of allylarenes via Ru-catalyzed S­(II)-directed aromatic C–H allylation reaction with vinylaziridines (c in Scheme ). The use of sulfur­(II) groups as directing groups has attracted some attention in recent years, despite their susceptibility to oxidation and potential poison to metal catalysts . In our study, the S­(II)-directed reaction was carried out using the Ru catalyst for first time and resulted in aromatic ortho -position C–H allylation of aryl methyl thioethers with E -configurated C–C double bonds rather than a mixture of Z / E isomers.…”

A Modular Approach to Atropisomeric Bisphosphines of Diversified Electronic Density on Phosphorus Atoms

“…Other strategies for the synthesis of chiral biaryl backbone include direct atroposelective biaryl coupling [ 39 , 40 ], as well as atroposelective aryl ring formation by cycloaddition reaction, and resolution and desymetrization methods etc. [ 1 , 41 , 42 , 43 , 44 , 45 , 46 ]. Although new developments in the synthesis of chiral biaryl skeleton are significant, some of them suffer from certain restrictions such as narrow substrate scope, low efficiency and inefficient stereocontrol.…”