Enantioselective Oxidation of 1,2-Diols with Quinine-Derived Urea Organocatalyst
摘要:
Quinine-derived urea has been identified as a highly efficient organocatalyst for the enantioselective oxidation of 1,2-diols using bromination reagents as the oxidant. This simple procedure utilizes readily available reagents and operates at ambient temperature to yield a wide range of a-hydroxy ketones in good yield (up to 94%) and excellent enantioselectivity (up to 95% ee).
GaN nanowires as a reusable photoredox catalyst for radical coupling of carbonyl under blacklight irradiation
作者:Mingxin Liu、Lida Tan、Roksana T. Rashid、Yunen Cen、Shaobo Cheng、Gianluigi Botton、Zetian Mi、Chao-Jun Li
DOI:10.1039/d0sc02718a
日期:——
level and energy band as a readily isolable and recyclable heterogeneous photoredox catalyst for radical coupling reactions. Using the carbonyl coupling reaction as a proof-of-concept, herein, we report a photo-pinacol coupling reaction catalyzed by GaN nanowires under ambient light at room temperature with methanol as a solvent and sacrificial reagent. By simply tuning the dopant, the GaN nanowire shows
CBZ6 as a Recyclable Organic Photoreductant for Pinacol Coupling
作者:Hua Wang、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.orglett.1c00537
日期:2021.4.16
% CBZ6)-catalyzed reductive (pinacol) coupling of aldehydes, ketones, and imines has been developed. Irradiated by purple light (407 nm) using triethylamine as an electron donor, a variety of 1,2-diols and 1,2-diamines could be prepared. The oxidation potential of the excited state of CBZ6 is established as −1.92 V (vs saturated calomel electrode (SCE)). The relative high reductive potential enables
Titanium-Catalyzed Reductive Umpolung Reactions with a Metal-Free Terminal Reducing Agent
作者:Georg Frey、J. Niklas Hausmann、Jan Streuff
DOI:10.1002/chem.201500102
日期:2015.4.7
A newmethod for titanium-catalyzed reductive umpolung reactions is reported that overcomes the traditional requirement for a stoichiometric metallic reductant. With N,N'-disilylated tetramethyldihydropyrazine as a potent organic reducing agent, reductive carbonyl-nitrile, enone-acrylonitrile and pinacolcouplingreactions can be achieved in good yields and stereoselectivities. [Cp2TiI2] is a superior
The influencing factors and marketing strategies of developing telecommunication industry customer loyalty
作者:Li Li、Wengui Su、Jian Jiang
DOI:10.1145/1089551.1089697
日期:——
In this paper, we analyze the influencing factors of the customer loyalty and set up the relational assess model, then apply analytic hierarchy process to establish the relation weights which influence the customer loyalty. At last, by means of applied instances in telecommunication industry, we represent the internal relations between the influencing factor weights and the customer loyalty and put forward marketing strategies on product and customer divergences to develop the customer loyalty.
A mild procedure for the reduction of electron-deficient alkenes and carbonyl compounds is described. UVA irradiations of substituted maleimides with dispersions of titania (Aeroxide P25) in methanol/acetonitrile (1:9) solvent under dry anoxic conditions led to hydrogenation and production of the corresponding succinimides. Aromatic and heteroaromatic aldehydes were reduced to primary alcohols in similar titania photocatalyzed reactions. A mechanism is proposed which involves two proton-coupled electron transfers to the substrates at the titania surface.