Pengxiang Zhang

Merging Photoredox with Copper Catalysis: Decarboxylative Alkynylation of α-Amino Acid Derivatives

A novel and efficient decarboxylative alkynylation of N-(acetoxy)phthalimides of α-amino acids with terminal alkynes has been developed by merging photoredox with copper catalysis at room temperature, and the reaction provided the valuable propargylamines in good to excellent yields with assistance of [Ru(bpy)3]Cl2/CuI and visible light. The simple protocol, mild reaction conditions, and high efficiency of this method make it an important strategy for synthesis of diverse molecules containing amino acid fragments.

Visible Light as a Sole Requirement for Intramolecular C(sp3)–H Imination

A novel, simple, and practical visible-light-mediated intramolecular α-C(sp3)-H imination of tertiary aliphatic amines containing β-O-aryl oximes leading to N-heterocycles has been developed. The reaction was performed well at rt with tolerance of some functional groups. Importantly, the selective C-H functionalization did not require added catalyst, oxidant, additive, acid, and base; visible light was the sole requirement.

Chiral Cyclic Ligand-Enabled Iridium-Catalyzed Asymmetric Arylation of Unactivated Racemic Allylic Alcohols with Anilines

A highly enantioselective arylation of unactivated racemic secondary allylic alcohols with aniline derivatives has been developed. The transformation was enabled by an iridium-chiral cyclic phosphoramidite complex in the presence of boron trifluoride diethyl etherate as the promoter, and the reactivity and enantioselectivity of the substrates were tuned by the variation of our newly developed chiral cyclic phosphoramidite ligands together with temperature and solvents. The method shows advantages including use of the readily available starting materials, an operationally convenient protocol, full regioselectivity and excellent enantioselectivity, and tolerance of many functional groups with water as the only byproduct.