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。
Luminescent tungsten(<scp>vi</scp>) complexes as photocatalysts for light-driven C–C and C–B bond formation reactions
作者:Daohong Yu、Wai-Pong To、Glenna So Ming Tong、Liang-Liang Wu、Kaai-Tung Chan、Lili Du、David Lee Phillips、Yungen Liu、Chi-Ming Che
DOI:10.1039/d0sc01340d
日期:——
gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C–C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
光催化在实际合成应用中的实现取决于开发可大规模制备的廉价光催化剂。本文描述了一种空气稳定、吸收可见光的光致发光钨 ( VI ) 配合物,可以方便地以克级制备。该配合物可催化光化学有机转化反应,包括芳基卤化物(如芳基氯)的硼化反应、苄基溴还原偶联以形成 C-C 键、苯酰溴的还原偶联以及烷基羧酸的氧化还原活性酯与高产率和广泛的官能团耐受性。
Converting <i>p</i>-terphenyl into a novel organo-catalyst for LED-driven energy and electron transfer photoreactions in water
作者:Maria-Sophie Bertrams、Christoph Kerzig
DOI:10.1039/d1cc01947c
日期:——
p-Terphenyl is a potent photoredox catalyst under UV-irradiation. Aiming for more sustainable reaction conditions, we added two sulfonate groups to this key structure to achieve water solubility and incorporated an SO2-bridge thereby shifting the absorption spectrum towards the visible. The resulting photocatalyst shows unexpected triplet reactivity in several test reactions.
对三联苯在紫外线照射下是一种有效的光氧化还原催化剂。为了获得更可持续的反应条件,我们在这个关键结构中添加了两个磺酸盐基团以实现水溶性,并引入了 SO 2桥,从而将吸收光谱移向可见光。所得光催化剂在几个测试反应中显示出意想不到的三线态反应性。
Parallel Paired Photoelectrochemical Bromination of Alkylarenes with Electrochemical Pinacol Coupling
作者:Hongshuai Chen、Chaoren Shen、Kaiwu Dong
DOI:10.1021/acs.joc.3c02556
日期:2024.2.16
A paired electrochemical method for paralleling benzylic bromination of alkylarenes under irradiation with reductive pinacol coupling in a divided cell has been developed. A variety of benzyl bromides at the anode and pinacols at the cathode were obtained simultaneously in moderate-to-high faradaic efficiency. This parallel paired electrochemical protocol showed a broad substrate scope and high chemoselectivity