Article
Multidisciplinary Sciences
Chia-Yu Huang, Jianbin Li, Chao-Jun Li
Summary: Hydrogen atom abstraction from C(sp(3))-H bonds of naturally abundant alkanes for alkyl radical generation represents a promising yet underexplored strategy in the alkylation reaction designs. The authors demonstrate a photo-induced and chemical oxidant-free cross-dehydrogenative coupling between alkanes and heteroarenes using catalytic chloride and cobalt catalyst, achieving successful couplings with satisfactory yields. The dual catalytic platform features the in situ engendered chlorine radical for alkyl radical generation and exploits the cobaloxime catalyst for catalytic turnover enabling hydrogen evolution.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Zeyu Shao, Junqi Zhou, Ziyu Wang, Biao Liu, Liang-Hua Zou, Cheng Wang, Jian Wen
Summary: A metal-free allylic C(sp(3))-H alkylation method based on [2,3]-sigmatropic rearrangement strategies has been developed, allowing the allylic C(sp(3))-H alkylation of a wide range of alpha-alkylstyryl sulfonium salts. This protocol enables facile access to allylated carbon quaternary centers in moderate to good yields. The one-pot procedure, product derivatization, and late-stage functionalization demonstrate the practicality of this protocol in organic synthesis.
ORGANIC CHEMISTRY FRONTIERS
(2023)
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.
Article
Multidisciplinary Sciences
Haigen Fu, Jingzhe Cao, Tianzhang Qiao, Yuyin Qi, Simon J. Charnock, Samuel Garfinkle, Todd K. Hyster
Summary: This study reports a highly chemoselective and enantioselective Csp(3)-Csp(3) XEC reaction catalyzed by flavin-dependent 'ene'-reductases (EREDs). The photoexcitation of the enzyme-templated charge-transfer complex enables the chemoselective reduction of alkyl halides and high enantioselectivity.
Article
Multidisciplinary Sciences
Chi Zhang, Zhong-Liang Li, Qiang-Shuai Gu, Xin-Yuan Liu
Summary: In recent years, there has been a renaissance in the enantioselective functionalization of common C(sp(3))-H bonds through a radical pathway. The authors summarize the main achievements in the field, identifying two main reaction pathways determining the stereochemistry, and provide an outlook on future challenges and opportunities.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Guo-Qiang Xu, Teng-Fei Xiao, Guo-Xuan Feng, Chen Liu, Baoxin Zhang, Peng-Fei Xu
Summary: The metal-free C(sp(3))-H aroylation of amines via visible-light photoredox catalysis provides a direct route for constructing a useful a-amino aryl ketone skeleton. Selected products show good biological activity for protecting PC12 cells, indicating the potential of this skeleton as a new neuroprotective agent. Mechanism experiments suggest that this transformation follows a photoredox catalytic radical-radical cross-coupling pathway.
Article
Chemistry, Multidisciplinary
Sean M. Treacy, Tomislav Rovis
Summary: By utilizing catalytic CuCl2, various feedstock chemicals can be functionalized through the coupling of unactivated C(sp(3))-H bonds with electron-deficient olefins. This reaction, enabled by Ligand-to-Metal Charge Transfer (LMCT), generates a chlorine radical capable of abstracting strong electron-rich C(sp(3))-H bonds. The protocol offers a simple operation and atom economical approach to generate a highly active hydrogen atom transfer reagent.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Bo Liu, Ming-Hua Xu
Summary: This study presents a new version of asymmetric carbene C-H insertion reaction using a rhodium(I) catalyst and chiral ligand, enabling efficient synthesis of a variety of chiral products at room temperature with excellent enantioselectivities. The synthetic utility of this method is demonstrated through the facile synthesis of a novel cannabinoid CB1 receptor ligand, suggesting potential for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Physical
Ying Huang, You-Feng Han, Chun-Lin Zhang, Song Ye
Summary: A straightforward and step-economy strategy for the modular synthesis of ketones through direct C-H alkylation of aldehydes with alkyl bromides under cooperative NHC/Pd catalysis at room temperature is reported. This simple process allows for the preparation of secondary and difficult-to-obtain tertiary alkyl-derived ketones under mild conditions. Mechanistic studies suggest the involvement of alkyl and ketyl radicals generated under NHC/Pd cooperative catalysis, followed by radical-radical coupling.
Article
Multidisciplinary Sciences
Qian-Yu Li, Shiyan Cheng, Ziqi Ye, Tao Huang, Fuxing Yang, Yu-Mei Lin, Lei Gong
Summary: This study developed a simplified photochemical system using iron(III) halides as multifunctional reagents and air as a green oxidant to achieve the direct and selective coupling of benzenes with aliphatic hydrocarbons. The method showed high yields and commendable chemo-, site-selectivity, and demonstrated the potential of iron halides in sustainable synthesis.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Yumei Huo, Beibei Chen, Zhaoqing Xu, Xiaoyu Ren, Rupeng Qi, Chao Wang
Summary: Heterobenzylic amines, such as alpha-alkyl-substituted oxadiazole methylamine skeletons, play important roles in pharmaceuticals and pesticides due to their unique biological activities. Photoredox reactions mediated by electron donor-acceptor (EDA) complexes have gained significant attention in the field of organic synthesis research due to their environmentally friendly nature. In this study, a C-H alkylation of heterobenzylic amines under visible light irradiation is reported, utilizing an EDA complex formed from alkyl iodide and organophosphines in catalytic amounts.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Heng Li, Jinwen Tong, Yan Zhu, Cong Jiang, Ping Liu, Peipei Sun
Summary: In this study, an efficient electrochemical Minisci reaction was developed to synthesize 3-hydroxyalkylquinoxalin-2(1H)-ones. The reaction involved hydrogen-atom transfer driven alpha-C(sp(3))-H functionalization of alcohols, and did not require transition metals or chemical oxidants. The reaction showed good compatibility with primary or secondary alcohols and a wide range of quinoxalinones, leading to high yields of the desired products.
Review
Chemistry, Organic
Mario Martinez Mingo, Nuria Rodriguez, Ramon Gomez Arrayas, Juan C. Carretero
Summary: Despite recent progress in C(sp(3))-H activation, achieving high regioselectivity in molecules with similar energy levels containing different C-H bonds remains a challenge. The use of directing groups and palladium catalysis in cyclometallation for direct C(sp(3))-H bond functionalization presents challenges in controlling selectivity and strategies.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Multidisciplinary Sciences
Shi Cao, Wei Hong, Ziqi Ye, Lei Gong
Summary: The study demonstrates the use of a dual asymmetric photocatalyst leading to the development of asymmetric sulfonylation involving direct functionalization of cycloalkanes, alkanes, toluene derivatives or ethers.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Wan-Xu Wei, Yuke Li, Ya-Ting Wen, Ming Li, Xue-Song Li, Cui-Tian Wang, Hong-Chao Liu, Yu Xia, Bo-Sheng Zhang, Rui-Qiang Jiao, Yong-Min Liang
Summary: This study reports a method for the synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem reaction, with the key step involving the activation of the δ-C-H bond to form a five-membered spiro-palladacycle intermediate. The CMD process, rate-determining step, and energy barrier of the entire reaction were explored through DFT calculations. Control experiments were conducted to investigate the rate-determining step and reversibility of the C(sp(3))-H activation step.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)