33470-10-9Relevant academic research and scientific papers
Electrochemical oxidation-induced benzyl C–H carbonylation for the synthesis of aromatic α-diketones
Tan, Yu-Fang,Chen, Yuan,Li, Rui-Xue,Guan, Zhi,He, Yan-Hong
supporting information, (2021/12/21)
Electrochemical oxidation-induced direct carbonylation of benzyl C–H bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in the air is used as an oxygen source.
Benzylic Aroylation of Toluenes Mediated by a LiN(SiMe3)2/Cs+System
Gu, Yuanyun,Zhang, Zhen,Wang, Yan-En,Dai, Ziteng,Yuan, Yaqi,Xiong, Dan,Li, Jie,Walsh, Patrick J.,Mao, Jianyou
supporting information, p. 406 - 418 (2022/01/14)
Chemoselective deprotonative functionalization of benzylic C-H bonds is challenging, because the arene ring contains multiple aromatic C(sp2)-H bonds, which can be competitively deprotonated and lead to selectivity issues. Recently it was found that bimetallic [MN(SiMe3)2 M = Li, Na]/Cs+ combinations exhibit excellent benzylic selectivity. Herein, is reported the first deprotonative addition of toluenes to Weinreb amides mediated by LiN(SiMe3)2/CsF for the synthesis of a diverse array of 2-arylacetophenones. Surprisingly, simple methyl benzoates also react with toluenes under similar conditions to form 2-arylacetophenones without double addition to give tertiary alcohol products. This finding greatly increases the practicality and impact of this chemistry. Some challenging substrates with respect to benzylic deprotonations, such as fluoro and methoxy substituted toluenes, are selectively transformed to 2-aryl acetophenones. The value of benzylic deprotonation of 3-fluorotoluene is demonstrated by the synthesis of a key intermediate in the preparation of Polmacoxib.
Synthesis of unsymmetrical ketones by applying visible-light benzophenone/nickel dual catalysis for direct benzylic acylation
Krach, Patricia E.,Dewanji, Abhishek,Yuan, Tingting,Rueping, Magnus
supporting information, p. 6082 - 6085 (2020/06/18)
Herein, we report a dual catalytic system for the direct benzylic C-H acylation reaction furnishing a variety of unsymmetrical ketones. A benzophenone-derived photosensitizer combined with a nickel catalyst has been established as the catalytic system. Both acid chlorides and anhydrides are able to acylate the benzylic position of toluene and other methylbenzenes. The method offers a valuable alternative to late transition metal catalyzed C-H acylation reactions.
Fukuyama Cross-Coupling Approach to Isoprekinamycin: Discovery of the Highly Active and Bench-Stable Palladium Precatalyst POxAP
Tang, Shuang-Qi,Bricard, Jacques,Schmitt, Martine,Bihel, Frédéric
, p. 844 - 848 (2019/01/30)
An efficient and user-friendly palladium(II) precatalyst, POxAP (post-oxidative-addition precatalyst), was identified for use in Fukuyama cross-coupling reactions. Suitable for storage under air, the POxAP precatalyst allowed reaction between thioesters and organozinc reagents with turnover numbers of ~90000. A series of 23 ketones were obtained with yields ranging from 53 to 99%. As proof of efficacy, an alternative approach was developed for the synthesis of a key precursor of the natural product isoprekinamycin.
Mn/Cu catalyzed addition of arylboronic acid to nitriles: Direct synthesis of arylketones
Moustafa, Dina,Sweet, Chelsea,Lim, Hyun,Calalpa, Brenda,Kaur, Parminder
, p. 3816 - 3820 (2018/09/18)
A direct and efficient synthesis of arylketones via arylboronic acid addition to nitriles in presence of inexpensive Mn/Cu catalytic system is reported. The use of non-precious Mn and Cu salts has been found to be highly advantageous both in terms of accessibility as well as cost effectiveness. A series of arylboronic acids as well as nitriles were used to synthesize a variety of symmetrical and unsymmetrical arylketones. Based on the literature studies, the reaction mechanism is anticipated to go through an aryl radical intermediate which reacted with the copper activated nitrile to give the desired arylketones after the hydrolysis of the imine intermediate.
Metal-free synthesis of ketones by visible-light induced aerobic oxidative radical addition of aryl hydrazines to alkenes
Ding, Ya,Zhang, Wenkai,Li, Hao,Meng, Yunge,Zhang, Te,Chen, Qiu-Yun,Zhu, Chunyin
supporting information, p. 2941 - 2944 (2017/07/24)
A green and cost-effective method has been developed for the conversion of alkenes to ketones under metal-free conditions. The reaction involves the oxidative addition of alkenes with aryl radicals, which are generated by visible-light induced aerobic oxidation of arylhydrazines. The key features of this reaction include broad substrate scope, readily available reagents and amenability to gram-scale synthesis.
Metal-free carbon-carbon cross-couplings between the ion pairs in sulfonium tetraphenylborates
Xu, Mei-Li,Huang, Wenhua
supporting information, p. 4230 - 4232 (2014/07/22)
A series of sulfonium tetraphenylborates can be readily prepared by the metathesis of sulfonium halides with sodium tetraphenylborates. After heating at 120-150 °C, the sulfonium tetraphenylborates can smoothly undergo the cross-couplings between the tetraphenylborate anions and the sulfonium cations in the absence of a metal catalyst. For carbonylmethyl-, benzyl-, and allylsulfoniums, the corresponding carbonylmethyl-phenyl, benzyl-phenyl, and allyl-phenyl cross-coupling products can be obtained in 22-76% yields. An interionic electron-transfer mechanism for this cross-coupling reaction is proposed.
Ruthenium-catalyzed cascade C-H functionalization of phenylacetophenones
Mehta, Vaibhav P.,Garcia-Lopez, Jose-Antonio,Greaney, Michael F.
supporting information, p. 1529 - 1533 (2014/03/21)
Three orthogonal cascade C-H functionalization processes are described, based on ruthenium-catalyzed C-H alkenylation. 1-Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p-cymene)Cl2}2] and stoichiometric Cu(OAc) 2. Each transformation uses C-H functionalization methods to form C-C bonds sequentially, with the indeno furanone synthesis featuring a C-O bond formation as the terminating step. This work demonstrates the power of ruthenium-catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple C-H functionalization steps taking place in a single operation to access novel carbocyclic structures. Carbon coupling cascade: Arylacetophenones react with Michael acceptors under ruthenium catalysis to set up triple and quadruple C-H functionalization pathways. Through choice of reaction conditions, novel indanone carbacycles, indeno indene carbacycles, and indeno furanone heterocycles can each be accessed in a single step.
