β-Cyclodextrin-NHC-Au(I)-Catalyzed Enantioconvergent 1,5-Enyne Cycloisomerizations.

Enantioconvergent transformations from racemic mixtures are attractive since they allow the generation of optically active products with full conversion despite the possibly adverse kinetic resolution process. When dealing with gold(I)-catalyzed cycloisomerizations, chirality transfer from the precursor is another possible diverting pathway, which renders enantioconvergence challenging. Not surprisingly, enantioconvergent Au(I)-catalyzed processes have remained extremely rare.

Visible-light-mediated phosphonylation reaction: formation of phosphonates from alkyl/arylhydrazines and trialkylphosphites using zinc phthalocyanine.

In this work, we developed a ligand- and base-free visible-light-mediated protocol for the photoredox syntheses of arylphosphonates and, for the first time, alkyl phosphonates. Zinc phthalocyanine-photocatalyzed Csp2-P and Csp3-P bond formations were efficiently achieved by reacting aryl/alkylhydrazines with trialkylphosphites in the presence of air serving as an abundant oxidant. The reaction conditions tolerated a wide variety of functional groups.

Visible-light-mediated semi-heterogeneous black TiO/nickel dual catalytic C (sp)-P bond formation toward aryl phosphonates.

The combination of black TiO nanoparticles (NPs) with a nickel catalyst provides a low-cost, sustainable, and reusable alternative dual catalytic system to a homogeneous counterpart (noble metals). This black TiO-photoredox/nickel dual catalytic system has efficiently driven C-P bond formation between aryl iodides and diarylphosphine oxides under visible light, providing good to excellent yields as well as tolerating a variety of functional groups. The practical application of this semi-heterogeneous protocol has been highlighted by a sunlight experiment, a gram-scale reaction, and a reusability test.