Stereoselective construction of highly functionalized heterocyclic molecules is an ongoing concern for the chemical community. Among the various strategies developed with this goal, catalytic asymmetric dearomatization, an attractive method for constucting cyclic molecules with multiple stereocenters from readily available aromatic compounds, has received extensive attention in recent years. Here, we report a highly stereoselective construction of tetrahydrofurobenzofurans and tetrahydrofurobenzothiophenes via palladium-catalyzed dearomative [3 + 2] cycloaddition of nitrobenzofurans and nitrobenzothiophenes, respectively. Good to excellent yields (63%-92%), diastereoselectivity (13/1 / >20/1 dr), and enantioselectivity (75%-95% ee) were obtained, leading to products with vicinal stereogenic carbon centers. The reaction features wide substrate scope and diverse transformations of the products.

A site-selective defluorinative sp3 C–H alkylation of secondary amides that rapidly and reliably incorporates gem-difluoroalkene motifs into previously unfunctionalized sp3 sites is disclosed. This protocol is distinguished by its mild conditions, wide scope, and exquisite site-selectivity, thus unlocking a new platform to introduce carbonyl isosteres at saturated hydrocarbon sites.

1,2-Bisphosphines have been identified as one class of important and powerfulc hiral ligands in asymmetric catalysis with transition metals.H erein, ac opper(I)-catalyzed asymmetric hydrophosphination of a,b-unsaturated phosphine sulfides was developed with the assistance of "soft-soft" interaction between copper(I)-catalyst and the phosphine sulfide moiety,w hich afforded 1,2-bisphosphine derivatives with diversified electronic nature and steric hindrance in high to excellent yields with high to excellent enantioselectivity. Moreover,the challenging catalytic asymmetric hydrophosphination/protonation reaction was achieved with excellent enantioselectivity.S trikingly,t he dynamic kinetic resolution of racemic diarylphosphines was also successfully carried out with high to excellent diastereo-and enantioselectivities. Interestingly,t he nucleophilic copper(I)-diphenylphosphide species was characterized by 31 PNMR spectrum and mass spectrum. At last, three products were transformed to chiral 1,2-bisphosphines,w hichw ere employed as ligands in Rhcatalyzeda symmetric hydrogenation of a-amino-a,b-unsaturated ester.The a-amino acid derivative was produced in high enantioselectivity,which demonstrated the utility of the present methodology.Scheme 1. Examples of reported chiral 1,2-bisphosphine ligands and working hypothesis to rapidly synthesize chiral 1,2-bisphosphine derivatives.Scheme 3. Application of synthesized chiral 1,2-bisphosphines in Rhcatalyzed asymmetric hydrogenation. Angewandte ChemieForschungsartikel 7127