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
105 for the reduction to alcohol and pinacol formation, respectively, and are very stable so that they can be recycled for at least 10 times in the reactions without significant loss of catalytic activity. The additional advantages of this method include good functional group tolerance, mild reaction conditions, the allowance of selectively reducing aldehydes in the presence of ketones, and easiness
Light-enabled metal-free pinacol coupling by hydrazine
作者:Zihang Qiu、Hanh D. M. Pham、Jianbin Li、Chen-Chen Li、Durbis J. Castillo-Pazos、Rustam Z. Khaliullin、Chao-Jun Li
DOI:10.1039/c9sc03737c
日期:——
Efficientcarbon–carbonbondformation is of great importance in modern organic synthetic chemistry. The pinacol coupling discovered over a century ago is still one of the most efficient coupling reactions to build the C–C bond in one step. However, traditional pinacol coupling often requires over-stoichiometric amounts of active metals as reductants, causing long-lasting metal waste issues and sustainability
高效的碳-碳键形成在现代有机合成化学中非常重要。一个多世纪前发现的频哪醇偶联仍然是一步构建 C-C 键的最有效偶联反应之一。然而,传统频哪醇偶联通常需要过量化学计量的活性金属作为还原剂,从而导致长期存在的金属废料问题和可持续性问题。一个巨大的科学挑战是设计一种无金属的频哪醇偶联反应方法。在这里,我们描述了一种光驱动频哪醇耦合协议,不使用任何金属,但使用 N 2 H 4,用作清洁的非金属氢原子转移 (HAT) 还原剂。在这种转化中,只有无痕无毒的N 2和H 2气体作为副产物产生,具有相对广泛的芳香酮范围和良好的官能团耐受性。对该机制的实验和计算研究表明,这种新颖的频哪醇偶联反应是通过光激发酮和 N 2 H 4之间的 HAT 过程进行的,而不是金属还原剂的常见单电子转移 (SET) 过程。
Application of coumarin dyes for organic photoredox catalysis
作者:Andrea Gualandi、Giacomo Rodeghiero、Emanuele Della Rocca、Francesco Bertoni、Marianna Marchini、Rossana Perciaccante、Thomas Paul Jansen、Paola Ceroni、Pier Giorgio Cozzi
DOI:10.1039/c8cc04048f
日期:——
Here we report the application of readily prepared and available coumarin dyes for photoredoxcatalysis, which are able to mimic powerful reductant [Ir(III)] complexes. Coumarin derivatives 9 and 10 were employed as photoreductants in pinacol coupling and in other reactions, in the presence of Et3N as a sacrificial reducing agent. As the electronic, photophysical, and steric properties of coumarins