Synthesis of Ferrocene Derivatives with Planar Chirality via Palladium-Catalyzed Enantioselective C–H Bond Activation
摘要:
The first catalytic and enantioselective C-H direct acylation of ferrocene derivative has been developed A series of 2-acyl-1-dimethylaminomethylferrocenes with planar chirality were provided under highly efficient and concise one-pot condition with up to 85% yield and 98% ee. The products obtained could be easily converted to various chiral ligands via diverse trans formations.
Use of 4-biphenylmethanol, 4-biphenylacetic acid and 4-biphenylcarboxylic acid/triphenylmethane as indicators in the titration of lithium alkyls. Study of the dianion of 4-biphenylmethanol
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
Photocatalytic Carbinol Cation/Anion Umpolung: Direct Addition of Aromatic Aldehydes and Ketones to Carbon Dioxide
作者:Shintaro Okumura、Yasuhiro Uozumi
DOI:10.1021/acs.orglett.1c02592
日期:2021.9.17
We have developed a new photocatalytic umpolung reaction of carbonyl compounds to generate anionic carbinol synthons. Aromaticaldehydes or ketones reacted with carbon dioxide in the presence of an iridium photocatalyst and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole (DMBI) as a reductant under visible-light irradiation to furnish the corresponding α-hydroxycarboxylic acids through nucleophilic
Photoredox Allylation Reactions Mediated by Bismuth in Aqueous Conditions
作者:Simone Potenti、Andrea Gualandi、Alessio Puggioli、Andrea Fermi、Giacomo Bergamini、Pier Giorgio Cozzi
DOI:10.1002/ejoc.202001640
日期:2021.3.19
Green Photoredox! Negligibly toxic bismuth salts can be employed in a photoredox allylation of aldehydes mediated by an organic dye. To further add interest to this new methodology, the photoredox Barbier allylation is carried out in EtOH/water and shows low sensitivity to oxygen and radical scavengers.
The Nozaki-Hiyamareaction can be performed in an enantioselective catalytic way! The catalytic system utilizes 10 mol % of an inexpensive chiral [Cr(salen)] complex. The [Cr(salen)]/Mn/Me(3)SiCl system effectively promotes the enantioselective addition of allyl chloride to aliphatic and aromatic aldehydes at room temperature (65-89 % ee, 40-60 % yield).
A first photocatalytic cross-pinacol coupling was achieved. The reaction proceeded with a various combination of two aldehydes, two ketones, or an aldehyde and a ketone to afford the corresponding unsymmetric vicinal 1,2-diols in up to 91 % yield. In this process, an umpoled anionic carbinol synthon was generated in situ, by the assistance of CO2 additive, to react nucleophilically with a second electrophilic
首次实现了光催化交叉频哪醇偶联。该反应以两种醛、两种酮或醛和酮的各种组合进行,以高达 91% 的产率提供相应的不对称邻位 1,2-二醇。在此过程中,在 CO 2添加剂的帮助下,原位生成了反极性的阴离子甲醇合成子,与第二个亲电子羰基化合物发生亲核反应。二氧化碳促进的光催化交叉频哪醇偶联(S. Okumura、Y. Uozumi 等)等)