Article
Chemistry, Organic
Jiayuan Wang, Youwan Ye, Tongzhi Sang, Chenxing Zhou, Xiazhen Bao, Yong Yuan, Congde Huo
Summary: A general C(sp3)-H/C(sp3)-H dehydrogenative coupling strategy for the preparation of various natural or unnatural amino acids from readily available glycine derivatives and hydrocarbons is reported, which involves a combination of SET and HAT process.
Article
Chemistry, Organic
Shuai Liu, Nivesh Kumar, Frederic Robert, Yannick Landais
Summary: A visible-light-mediated intramolecular site-selective delta-C(sp3)-H bond arylation of aliphatic trifluoromethanesulfonamides was developed. The reaction proceeds through a radical cascade, involving the generation of a sulfonamidyl radical, 1,5-hydrogen atom transfer, formation of a delta-C-centered radical, and finally cyclization onto a neighboring thiopolyfluoroaryl moiety to provide thiochromanes. The cyclization process occurs via two distinct pathways depending on the substituent X ortho to the native C-S bond.
Review
Chemistry, Multidisciplinary
Jayabrata Das, Wajid Ali, Debabrata Maiti
Summary: In this review, the development of C(sp3)-H activation is highlighted, including its origins, progression, and overcoming of limitations, to identify future research directions. The three main strategies for C(sp3)-H activation in aliphatic molecules are static directing group (DG) or template-assisted approach, transient DG (TDG) approach, and native functional group (NFG)-assisted approach. Each section provides a brief discussion on the evolution, functionalization type, advantages, and shortcomings of C(sp3)-H activation.
TRENDS IN CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Enzo Nobile, Thomas Castanheiro, Tatiana Besset
Summary: Fluorinated scaffolds play a pivotal role in pharmaceuticals, agrochemicals, and materials science. Recent attention has focused on the development of versatile strategies for the selective synthesis of fluorinated molecules through direct C-H bond functionalization, particularly in designing novel transformations based on radical processes to introduce fluorinated groups.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Shanxue Zhang, Yufeng Li, Tao Wang, Ming Li, Lirong Wen, Weisi Guo
Summary: In this study, we report an electrochemical benzylic isothiocyanation method with high chemoselectivity and site-selectivity under oxidant-free conditions. The method is notable for its compatibility with functional groups and its suitability for late-stage functionalization of bioactive molecules.
Article
Chemistry, Multidisciplinary
Liang Hu, Guangrong Meng, Jin-Quan Yu
Summary: This study reports the first Pd(II)-catalyzed intermolecular fi-methylene C(sp3)-H arylation of free aliphatic acids using bidentate pyridine-pyridone ligands. The bite angle of the ligand plays a key role in promoting fi-methylene C-H activation of free carboxylic acid. This transformation provides a disconnection for alkylation of arenes with simple aliphatic acids.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Fangyuan Yu, Sen Yang, Zihao Xie, Dengfu Lu, Yuefa Gong
Summary: This article reports an iron-catalysed selective C-((sp3))-H alkylation method for glycine derivatives, which converts N-aryl glycinates into a series of pyrroline-containing amino esters using gamma,delta-unsaturated oxime esters as both the alkylation reagent and terminal oxidant. The ligand plays a key role in tuning the chemoselectivity, and a radical-polar crossover pathway is proposed according to the mechanistic studies. Additionally, the products obtained with this method can be transformed into various valuable building blocks.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Sergio Sisti, Marco Galeotti, Filippo Scarchilli, Michela Salamone, Miquel Costas, Massimo Bietti
Summary: A detailed study on C(sp(3))-H bond oxygenation reactions catalyzed by [Mn(OTf)(2)((TIPS)mcp)] complex was conducted, showing that the introduction of electron-withdrawing functional groups in different solvents significantly increased site-selectivity and product yield. The study also achieved selective control over multiple methylenic sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Biao Wang, Min-Jie Zhou, Qi-Lin Zhou
Summary: Here, we present a novel protocol for visible-light-induced α,γ-C(sp3)-H difunctionalization of piperidines. This redox-neutral, atom-economical protocol, which has a wide substrate scope and good functional group compatibility, offers a concise and practical method for constructing piperidine-containing bridged-ring molecules. Preliminary mechanistic studies indicate that the highly regioselective activation of the inert γ-C(sp3)-H bond of piperidines is achieved through a 1,5-hydrogen atom transfer reaction of a nitrogen radical generated in situ.
Article
Chemistry, Organic
Ming-Shun Mei, Yanghui Zhang
Summary: A new approach for the synthesis of naphthalimides via a tandem reaction of o-methylbenzaldehydes and maleimides is developed in this work. The reaction involves Pd(II)-catalyzed benzylic C(sp(3))-H oxidation using an amino acid as the transient directing group and Diels-Alder reaction. The subsequent dehydration forms naphthalimides, allowing for easy access to a range of naphthalimides with a variety of substituents.
Article
Chemistry, Physical
Bryan C. Figula, Ting-An Chen, Jeffery A. Bertke, Timothy H. Warren
Summary: In this study, a radical relay C-H methylation method using a beta-diketiminate copper catalyst was developed, enabling the methylation of unactivated C(sp(3))-H bonds. By utilizing the bench-stable DABAL-Me-3 as a reagent, methylation of various substrates with both activated and unactivated C(sp(3))-H bonds was achieved with minimal overmethylation. Mechanistic studies suggested the involvement of a copper(II) methyl intermediate that reacts with methyl radicals and radicals R-center dot to form R-Me bonds.
Article
Chemistry, Organic
Di Fang, Yidan Zhang, Yiyun Chen
Summary: In this study, a novel photoredox catalysis method was reported for selective synthesis of delta- and epsilon-alkenols from aliphatic alcohols. N-Alkoxybenzimidoyl chlorides were used as alkoxyl radical precursors with tunable redox potentials, allowing for the construction of various alkenols through the inert C(sp(3))-H Heck-type reaction.
Article
Chemistry, Multidisciplinary
Alexander Fawcett, M. Josephine Keller, Zachary Herrera, John F. Hartwig
Summary: A highly selective method for chlorination of tertiary and benzylic C(sp(3))-H bonds has been developed, utilizing azidoiodinane and a copper(II) chloride complex to generate the corresponding chlorides in high yields. The reaction shows exceptional functional group tolerance, allowing for chlorination of diverse substrates and late-stage chlorination of derivatives of natural products and active pharmaceutical ingredients.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
A. Young Ji, Annaram Thirupathi, Joon Young Hwang, Yuri Kim, Gyuri Han, Kwang-Hyun Ahn, Kyungtae Kang, Eun Joo Kang
Summary: The Fe-III(phen)(3) catalysis of the benzylic C(sp(3))-H azidation of indoles has been studied. The Fe(III) complex can selectively oxidize indoles to form arene radical cations, which are transformed into benzylic C(sp(3)) radical intermediates. This strategy exhibits a difference in reactivity between N-heteroarenes and benzene, which is difficult to achieve via direct hydrogen abstraction approaches. Various biorelevant azide precursors were constructed, highlighting the utility of this mild first-row transition-metal catalyst system.
Article
Chemistry, Organic
A. Young Ji, Annaram Thirupathi, Joon Young Hwang, Yuri Kim, Gyuri Han, Kwang-Hyun Ahn, Kyungtae Kang, Eun Joo Kang
Summary: The FeIII(phen)3 catalysis of benzylic C(sp3)-H azidation of indoles was studied. The Fe(III) complex can selectively oxidize indoles to form arene radical cations, which further transform into benzylic C(sp3) radical intermediates. This strategy exhibits a difference in reactivity between N-heteroarenes and benzene, which is difficult to achieve via direct hydrogen abstraction approaches. Various biorelevant azide precursors were synthesized, demonstrating the utility of this mild first-row transition-metal catalyst system.