Metal-free construction of dihydropyrazino[2,3-]indoles from 2-aminoacetophenones, isocyanates and 1,2-diamines.

A Brønsted acid/iodine co-mediated approach to construct dihydropyrazino[2,3-]indoles in 2-MeTHF as a green solvent at room temperature was established. A wide range of diversely substituted dihydropyrazino[2,3-]indoles (42 examples, 61-85% yields) were synthesized under mild conditions, even on a gram scale. This protocol features organocatalysts, an eco-friendly solvent, mild conditions, readily accessible substrates, broad substrate scope and simple work-up.

Photocatalytic C-H Activation and Amination of Arenes with Nonactivated -Hydroxyphthalimides Involving Phosphine-Mediated N-O Bond Scission.

Herein, we reported a metal-free photoredox/phosphine-catalyzed C-H amination of arenes. This allows for concise synthesis of highly functionalized -arylphthalimides from readily available -hydroxyphthalimides directly, without the preparation of activated -hydroxyphthalimide intermediates. Mechanistic studies reveal that the radical is produced via phosphine-mediated N-O bond scission.

Employing Visible-Light Photoredox Catalysis in Multicomponent-Multicatalyst Reactions: One-Pot Synthesis of Spiroquinazolin-2-(thi)ones.

The multicomponent-multicatalyst reaction ((MC)R) and visible-light catalysis have emerged as green and powerful strategies for achieving ideal syntheses. Here, we report the first example of a visible-light-induced approach toward spiroquinazolin(thi)ones. This (MC)R features an eco-friendly energy source and solvent, metal-free catalysts, step- and atom-economy, a relay catalysis strategy, air as green oxidant, mild conditions, and easily accessible starting materials.

B(CF)-Catalyzed Asymmetric Reductive Amination of Ketones with Ammonia Borane.

The first example of metal-free B(CF)-catalyzed asymmetric reduction amination of ketones with chiral α-methylbenzylamine (α-MBA) using ammonia borane as the reductant is reported. This one-pot method has a broad substrate scope and provides various chiral amines in 81-95% yield with 80-99% de. This protocol was further applied in the total synthesis of cinacalcet.

[Effect of activated charcoal on rooting in tissue culture seedling of Begonia fimbristipula on Dinghushan Mountain].

Objective: To study the effect of different plant growth substance and activated charcoal on rooting in culture seedling of Begonia fimbristpula on Dinghushan mountain.

Methods: Tissue culture single factor experiment method was used.

Results: NAA 0.