Elaborating Complex Heteroaryl‐Containing Cycles via Enantioselective Palladium‐Catalyzed Cycloadditions

A general method for asymmetric synthesis of heteroaryl‐containing cycles via palladium‐catalyzed cyclization is reported. Most classes of nitrogen‐containing aromatics, including pyridines, quinolines, pyrimidines, various azoles and the derivatives of nucleobases are compatible substrates, offering various heteroaryl‐substituted cyclopentane, pyrrolidine, furanidine and bicyclo[4.3.1]decadiene derivatives with good to excellent enantioselectivity and diastereoselectivity.     

Asymmetric Lewis Acid Catalyzed Electrochemical Alkylation

Lewis‐acid catalysis and electrochemistry represent two powerful fields that have found widespread application in organic chemistry. Reported herein is an asymmetric electrosynthesis in combination with a chiral Ni catalyst leading to an intermolecular alkylation reaction in good yields with excellent enantioselectivities (up to 97 % ee). Mechanistic studies suggest that the Lewis‐acid‐bound radical intermediate from a single‐electron anodic oxidation selectively reacts with the benzylic radical species to generate the desired adducts.     

Rhodium‐Catalyzed Enantioselective Radical Addition of CX4 Reagents to Olefins

We describe the synthetically useful enantioselective addition of Br−CX₃ (X=Cl or Br) to terminal olefins to introduce a trihalomethyl group and generate optically active secondary bromides. Computational and experimental evidence supports an asymmetric atom‐transfer radical addition (ATRA) mechanism in which the stereodetermining step involves outer‐sphere bromine abstraction from a [(bisphosphine)Rh^IIBrCl] complex by a benzylic radical intermediate. This mechanism appears unprecedented in asymmetric catalysis.     

Pd‐Catalyzed Dearomatization of Anthranils with Vinylcyclopropanes by [4+3] Cyclization Reaction

Dearomatization of anthranils with vinylcyclopropanes (VCPs) by Pd‐catalyzed [4+3] cyclization reaction has been realized. In the presence of a catalytic amount of borane as an activator, bridged cyclic products were obtained in good to excellent yields with excellent stereoselectivities. By introducing a chiral PHOX ligand ( L5 ), asymmetric dearomatization reactions of anthranils with vinylcyclopropanes proceeded with excellent enantioselectivity. Borane plays a key role for the reactivity, likely owing to the formation of a borane–anthranil complex which has been confirmed by NMR experiments.