7555-67-1Relevant academic research and scientific papers
Oxidative Ring Expansion of Cyclobutanols: Access to Functionalized 1,2-Dioxanes
Lapez, Mara-A Marta-N,Jamey, Nicolas,Pinet, Alexis,Figadeìre, Bruno,Ferri, Laurent
supporting information, p. 1626 - 1631 (2021/03/08)
Cyclobutanols undergo an oxidative ring expansion with Co(acac)2 and triplet oxygen to give 1,2-dioxanols. The formation of an alkoxy radical drives the regioselective cleavage of the ring on the more substituted side before insertion of molecular oxygen. The reaction is particularly effective on secondary cyclobutanols but works also on certain tertiary alcohols. Further substitution with neutral nucleophiles under catalytic Lewis acid conditions led to original 1,2-dioxanes with a preferred 3,6-cis-configuration.
Iron-Catalyzed Regioselective Alkenylboration of Olefins
Yu, Xiaolong,Zheng, Hongling,Zhao, Haonan,Lee, Boon Chong,Koh, Ming Joo
supporting information, p. 2104 - 2109 (2020/11/30)
The first examples of an iron-catalyzed three-component synthesis of homoallylic boronates from regioselective union of bis(pinacolato)diboron, an alkenyl halide (bromide, chloride or fluoride), and an olefin are disclosed. Products that bear tertiary or quaternary carbon centers could be generated in up to 87 % yield as single regioisomers with complete retention of the olefin stereochemistry. With cyclopropylidene-containing substrates, ring cleavage leading to trisubstituted E-alkenylboronates were selectively obtained. Mechanistic studies revealed reaction attributes that are distinct from previously reported alkene carboboration pathways.
Gem-Difluorination of Methylenecyclopropanes (MCPs) Featuring a Wagner-Meerwein Rearrangement: Synthesis of 2-Arylsubstituted gem-Difluorocyclobutanes
Lin, Peng-Peng,Huang, Long-Ling,Feng, Si-Xin,Yang, Shuang,Wang, Honggen,Huang, Zhi-Shu,Li, Qingjiang
supporting information, p. 3088 - 3093 (2021/05/05)
The geminal difluorocyclobutane core is a valuable structural element in medicinal chemistry. Strategies for gem-difluorocyclobutanes, especially the 2-substituted cases, are limiting and often suffer from harsh reaction conditions. Reported herein is a m
Copper-Catalyzed Enantioselective Arylation via Radical-Mediated C-C Bond Cleavage: Synthesis of Chiral ω,ω-Diaryl Alkyl Nitriles
Cui, Guo-Qing,Dai, Jing-Cheng,Li, Yan,Li, Yuan-Bo,Hu, Duo-Duo,Bian, Kang-Jie,Sheng, Jie,Wang, Xi-Sheng
supporting information, p. 7503 - 7507 (2021/10/02)
The first example of copper-catalyzed ring-opening, enantioselective arylation of cyclic ketoxime esters to access ω,ω-diaryl alkyl nitriles has been developed in high yield (up to 92% yield) with excellent enantioselectivity (up to 91% ee). Side-arm bis(oxazoline) ligand plays a significant role in this asymmetric catalytic transformation, which provides an efficient route to construct diverse chiral ω,ω-diaryl alkyl nitriles. Synthetic utility has also been demonstrated in the further derivatization of the ω,ω-diaryl alkyl nitrile to the corresponding amide.
Visible-Light Photoredox-Catalyzed Dicarbofunctionalization of Styrenes with Oxime Esters and CO2: Multicomponent Reactions toward Cyanocarboxylic Acids and γ-Keto Acids
Bai, Junxue,Li, Miao,Zhou, Cong,Sha, Yu,Cheng, Jiang,Sun, Jianwei,Sun, Song
supporting information, p. 9654 - 9658 (2021/12/14)
A photoredox-catalyzed dicarbofunctionalization of styrenes with oxime esters and CO2 has been achieved. Notably, a series of four-, five-, or six-membered cyclic ketone oximes worked well to furnish a wide range of ε-, ζ-, and η-cyanocarboxylic acids in good yields. Furthermore, a series of γ-keto acids also could be obtained by employing acyclic ketone oxime esters as the carbonyl radical precursor. It provides convergent access to diverse biologically important cyanocarboxylic and γ-keto acids.
Nickel-Catalyzed Favorskii-Type Rearrangement of Cyclobutanone Oxime Esters to Cyclopropanecarbonitriles
Fang, Ping,Mei, Tian-Sheng,Shuai, Bin
supporting information, p. 1637 - 1641 (2021/10/02)
A nickel-catalyzed base-promoted rearrangement of cyclobutanone oxime esters to cyclopropanecarbonitriles was developed. The ring opening of cyclobutanone oxime esters occurs at the sterically less hindered side. A base-promoted nickelacyclobutane intermediate, formed in situ, is assumed to be involved in the formation of the product.
Cobalt(iii)-catalyzed redox-neutral [4+2]-annulation ofN-chlorobenzamides/acrylamides with alkylidenecyclopropanes at room temperature
Ramesh, Balu,Jeganmohan, Masilamani
supporting information, p. 3692 - 3695 (2021/04/16)
An efficient synthesis of substituted 3,4-dihydroisoquinolinones through [4+2]-annulation ofN-chlorobenzamides/acrylamides having a monodentate directing group with alkylidenecyclopropanes in the presence of a less expensive, highly abundant and air stable Co(iii) catalystviaa C-H activation is demonstrated. In this reaction, the N-Cl bond ofN-chlorobenzamide serves as an internal oxidant and thus an external metal oxidant is avoided. The 3,4-dihydroisoquinolinone derivatives are converted successfully into the highly useful imidoyl chloride derivatives. The deuterium labeling and kinetic isolabelling studies reveal that the C-H activation is a rate-determining step in this cyclization reaction.
Radical-Cation Vinylcyclopropane Rearrangements by TiO2Photocatalysis
Maeta, Naoya,Kamiya, Hidehiro,Okada, Yohei
, p. 6551 - 6566 (2020/07/14)
Radical cation vinylcyclopropane rearrangements by TiO2 photocatalysis in lithium perchlorate/nitromethane solution are described. The reactions are triggered by oxidative single electron transfer, which is followed by immediate ring-opening of the cyclopropanes to generate distonic radical cations as unique reactive intermediates. This approach can also be applied to vinylcyclobutane, leading to the construction of six-membered rings. A stepwise mechanism via distonic radical cations is proposed based on preliminary mechanistic studies, which is supported by density functional theory calculations.
TFA-Catalyzed [3+2] Spiroannulation of Cyclobutanols: A Route to Spiro[cyclobuta[a]indene-7,1′-cyclobutane] Skeletons
An, Zhenyu,Liu, Yafeng,Sun, Yanwei,Yan, Rulong
supporting information, p. 3812 - 3815 (2020/10/19)
A straightforward method for the synthesis of spiro[cyclobuta[a]indene-7,1′-cyclobutane] derivatives from cyclobutanols has been developed via one-pot [3+2] spiroannulation. A series of new spiro[cyclobuta[a]indene-7,1′-cyclobutane] derivatives are facile
Strain-Promoted Oxidation of Methylenecyclopropane Derivatives using N-Hydroxyphthalimide and Molecular Oxygen in the Dark
Anderson, T. E.,Woerpel, K. A.
supporting information, (2020/07/30)
The hydroperoxidation of alkylidenecyclopropanes and other strained alkenes using an N-hydroxylamine and molecular oxygen occurred in the absence of catalyst, initiator, or light. The oxidation reaction proceeds through a radical pathway that is initiated by autoxidation of the alkene substrate. The hydroperoxides were converted to their corresponding alcohols and ketones under mild conditions.
