在这项研究中,通过改变苯氢安息香主链上苯基的结合位置来设计模块化配体结构。合成并表征了衍生自该模块化C 2对称配体的一系列区域异构取代的邻苯二甲腈。然后,从苯二腈衍生物与氯化钴(II)的反应中获得了八种钴(II)酞菁(CoPc)。使用叔丁基氢过氧化物作为氧源并在N-存在下,测试了合成的钴(II)酞菁钴的催化活性对乙腈中的苄醇氧化溴丁二酰亚胺作为添加剂在80°C下反应5小时。从这个意义上说,为了获得最高的苯甲醛选择性(高达83%),已详细研究了底物与催化剂的比例和氧化剂与催化剂的比例的影响。还阐明了在酞菁骨架的外围或非外围位置的取代基的结构设计对钴(II)酞菁在苄醇氧化中的催化活性性能的影响。所有新合成的化合物均具有FT-IR,1 H NMR,IR,UV-Vis和MALDI-TOF MS光谱数据。
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
of manganese as a mediator for allylations and pinacol couplings in aqueousmedia was investigated. The combination of manganese and copper is found to be a highly effective mediator for the allylation of aryl aldehydes in water. Such a combination is found to be more reactive than other previously reported metals in aqueousmedia. No reaction was observed with either manganese or copper alone as the
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
high reduction potential of carbonyl compounds and imines. In the context of photoredox catalysis, tertiary amines are commonly employed as sacrificial co‐reducing agents. Herein, an additional role of the amine is proposed, in which it is essential for the organocatalytic substrate activation. The combination of photoredox catalysis and carbonyl/imine activation enables the reductivecoupling of aldehydes
A novel catalytic pinacol coupling utilising 3 mol % of the readily available rac-ethylenebis(η5-tetrahydroindenyltitanium) dichloride (EBTHITiCl2) as catalyst is described. Diastereoselectivities are in excess of 95:5. The reaction conditions for the coupling of aromatic aldehydes are mild and tolerate a variety of functional groups interfering with dihydroxylation reactions and McMurry coupling reactions.