Photoinduced decarboxylative borylation of carboxylic acids
作者:Alexander Fawcett、Johan Pradeilles、Yahui Wang、Tatsuya Mutsuga、Eddie L. Myers、Varinder K. Aggarwal
DOI:10.1126/science.aan3679
日期:2017.7.21
283 Light facilitates the replacement of carboxylic acids with boron esters in the absence of metal catalysts. The conversion of widely available carboxylic acids into versatile boronic esters would be highly enabling for synthesis. We found that this transformation can be effected by illuminating the N-hydroxyphthalimide ester derivative of the carboxylic acid under visible light at room temperature
Decarboxylative Borylation of Stabilized and Activated Carbon Radicals
作者:Qiang Zhang、Xiaojuan Li、Weigang Zhang、Shengyang Ni、Yi Wang、Yi Pan
DOI:10.1002/anie.202008138
日期:2020.12
aliphatic and aromatic boronic esters by mild photoinduced decarboxylativeborylation. Both aryl and alkyl radicals could be generated from the leaving group‐assisted N‐hydroxybenzimidoyl chloride esters, even α‐CF3 substituted substrates could be activated for further elaboration.
Decarboxylative Borylation of Aliphatic Esters under Visible-Light Photoredox Conditions
作者:Dawei Hu、Linghua Wang、Pengfei Li
DOI:10.1021/acs.orglett.7b01181
日期:2017.5.19
methods for preparing alkyl boronates often necessitate anhydrous and demanding reaction conditions. Herein, a new, operationally simple decarboxylative borylation reaction of readily available aliphaticacid derivatives under additive-free visible-light photoredox conditions in nonanhydrous solvents has been described. Primary and secondary alkyl boronates or tetrafluoroborates with various functional
We proposed a Minisci-type strategy for the alkylation of heterocycles with a variety of boron species under low cost and easily scale-up conditions without the use of transition-metal or organo-catalysts. The extension of this strategy to other systems will provide green approaches for the post-modifications of drug molecules and complex natural products.
We present herein a novel photo‐mediated homolytic C‐S bond formation for the preparation of alkylthiopurines and alkylthiopurine nucleosides. Despite the presence of reactive sites for the Minisci reaction, chemoselective S‐alkylation remained the predominant pathway. This method allows for the late‐stage introduction of a broad spectrum of alkyl groups onto the sulfur atom of unprotective mercaptopurine derivatives, encompassing 2‐, 6‐, and 8‐mercaptopurine rings. Organoborons serve as efficient and eco‐friendly alkylating reagents, providing advantages in terms of readily availability, stability, and reduced toxicity. Further derivatization of the thioetherified nucleosides, together with anti‐tumor assays, led to the discovery of potent anti‐tumor agents with an IC50 value reaching 6.1 µM (Comp. 31 for Jurkat).