scholarly journals Electrochemical C-C Bond Cleavage of Cyclopropanes towards the Synthesis of 1,3-Difunctionalized Molecules

2020 ◽  
Author(s):  
Pan Peng ◽  
Xingxiu Yan ◽  
Ke Zhang ◽  
Zhao Liu ◽  
Li Zeng ◽  
...  
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Radical Cation ◽  
Redox Reactions ◽  
Bond Cleavage ◽  
Strategic Choice ◽  
Mechanistic Studies ◽  
Catalyst Free ◽  
Electrochemical Condition ◽  
Anode Oxidation

Abstract Electrochemistry had a lot of inherent advantages in organic synthesis and many redox reactions have been achieved under electrochemical condition. However, the electrochemical C-C bond cleavage and functionalization reactions are less studied. Here we developed electrochemical C-C bond cleavage and 1,3-difuntionalization of arylcyclopropanes under catalyst-free and external-oxidant-free conditions. 1,3-difluorination, 1,3-oxyfluorination and 1,3-dioxygenation of arylcyclopropanes were achieved with a highly chemo- and regioselectivity by the strategic choice of nucleophiles. This protocol has good functional groups tolerance and can be scaled up. Mechanistic studies demonstrate that arylcyclopropane radical cation yielded from the anode oxidation and the following generated benzyl carbonium are the key intermediates in this transformation. This development provides a new scenario for constructing 1,3-difunctionalized molecules.

scholarly journals Electrochemical C−C bond cleavage of cyclopropanes towards the synthesis of 1,3-difunctionalized molecules

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pan Peng ◽  
Xingxiu Yan ◽  
Ke Zhang ◽  
Zhao Liu ◽  
Li Zeng ◽  
...  
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Radical Cation ◽  
Redox Reactions ◽  
Bond Cleavage ◽  
Strategic Choice ◽  
Mechanistic Studies ◽  
Catalyst Free ◽  
Electrochemical Condition ◽  
Anode Oxidation

AbstractElectrochemistry has a lot of inherent advantages in organic synthesis and many redox reactions have been achieved under electrochemical condition. However, the electrochemical C−C bond cleavage and functionalization reactions are less studied. Here we develop electrochemical C−C bond cleavage and 1,3-difuntionalization of arylcyclopropanes under catalyst-free and external-oxidant-free conditions. 1,3-difluorination, 1,3-oxyfluorination and 1,3-dioxygenation of arylcyclopropanes are achieved with a high chemo- and regioselectivity by the strategic choice of nucleophiles. This protocol has good functional groups tolerance and can be scaled up. Mechanistic studies demonstrate that arylcyclopropane radical cation obtained from the anode oxidation and the subsequently generated benzyl carbonium are the key intermediates in this transformation. This development provides a scenario for constructing 1,3-difunctionalized molecules.

scholarly journals Photoredox-catalyzed oxo-amination of aryl cyclopropanes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Liang Ge ◽  
Ding-Xing Wang ◽  
Renyi Xing ◽  
Di Ma ◽  
Patrick J. Walsh ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Driving Force ◽  
Ring Opening ◽  
Bond Cleavage ◽  
Building Blocks ◽  
Nucleophilic Attack ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
One Pot ◽  
Thermodynamic Driving Force

Abstract Cyclopropanes represent a class of versatile building blocks in modern organic synthesis. While the release of ring strain offers a thermodynamic driving force, the control of selectivity for C–C bond cleavage and the subsequent regiochemistry of the functionalization remains difficult, especially for unactivated cyclopropanes. Here we report a photoredox-coupled ring-opening oxo-amination of electronically unbiased cyclopropanes, which enables the expedient construction of a host of structurally diverse β-amino ketone derivatives. Through one electron oxidation, the relatively inert aryl cyclopropanes are readily converted into reactive radical cation intermediates, which in turn participate in the ensuing ring-opening functionalizations. Based on mechanistic studies, the present oxo-amination is proposed to proceed through an SN2-like nucleophilic attack/ring-opening manifold. This protocol features wide substrate scope, mild reaction conditions, and use of dioxygen as an oxidant both for catalyst regeneration and oxygen-incorporation. Moreover, a one-pot formal aminoacylation of olefins is described through a sequential cyclopropanation/oxo-amination.

scholarly journals Cycloaddition of Thiourea- and Guanidine-Substituted Furans to Dienophiles: A Comparison of the Environmentally-Friendly Methods

2020 ◽  
Vol 3 (1) ◽  
pp. 57
Author(s):  
Luka Barešić ◽  
Davor Margetić ◽  
Zoran Glasovac
Keyword(s):  
High Pressure ◽  
Functional Groups ◽  
Organic Synthesis ◽  
High Speed ◽  
Environmentally Friendly ◽  
Microwave Assisted ◽  
Pressure Synthesis ◽  
Ultrasound Assisted ◽  
Substituted Furans ◽  
Guanidine Moiety

The cycloaddition strategy was employed in order to obtain a 7-oxanorbornene framework substituted with a guanidine moiety or its precursor functional groups: protected amine or thiourea. In order to optimize the conditions for the cycloaddition, several environmentally-friendly methods—microwave assisted organic synthesis, high pressure synthesis, high speed vibrational milling, and ultrasound assisted synthesis—were employed. The outcomes of the cycloaddition reactions were interpreted in terms of endo/exo selectivity, the conversion of the reactants to the product, and the isolated yields. In general, our results indicated the HP and HSVM approaches as the methods of choice to give good yields and conversions.

Preyssler heteropolyacid H14[NaP5W29MoO110]: A heterogeneous, green and recyclable catalyst used for the protection of functional groups in organic synthesis

2010 ◽  
Vol 161 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Gustavo Romanelli ◽  
Diego Ruiz ◽  
Patricia Vázquez ◽  
Horacio Thomas ◽  
Juan C. Autino
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Recyclable Catalyst

Ultrasonically dispersed potassium in organic synthesis. Water-acceleration in reductive CS bond cleavage reactions

1991 ◽  
Vol 32 (29) ◽  
pp. 3551-3554 ◽  
Author(s):  
Ta-shue Chou ◽  
Shao-Hwa Hung ◽  
Man-Li Peng ◽  
Shwu-Jiaun Lee
Keyword(s):  
Organic Synthesis ◽  
Bond Cleavage ◽  
Cleavage Reactions

Mechanistic Studies in the Radical Induced DNA Strand Cleavage—Formation and Reactivity of the Radical Cation Intermediate

Tetrahedron ◽  
2000 ◽  
Vol 56 (25) ◽  
pp. 4117-4128 ◽  
Author(s):  
Ralf Glatthar ◽  
Martin Spichty ◽  
Andreas Gugger ◽  
Rohit Batra ◽  
Wolfgang Damm ◽  
...  
Keyword(s):  
Radical Cation ◽  
Mechanistic Studies ◽  
Dna Strand

scholarly journals Controlling Non-Native B12 Reactivity and Catalysis in the Transcription Factor CarH

2021 ◽  
Author(s):  
Xinhang Yang ◽  
Benjamin H. R. Gerroll ◽  
Yuhua Jiang ◽  
Amardeep Kumar ◽  
Yasmine S. Zubi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Vitamin B12 ◽  
Transcription Regulation ◽  
Bond Cleavage ◽  
Oxidative Addition ◽  
Mechanistic Studies ◽  
Organic Transformations ◽  
Carbon Bond ◽  
Wide Range ◽  
Hydride Elimination

Vitamin B12 derivatives catalyze a wide range of organic transformations, but B12-dependent enzymes are underutilized in biocatalysis relative to other metalloenzymes. In this study, we engineered a variant of the transcription factor CarH, called CarH*, that catalyzes styrene C-H alkylation with improved yield and selectivity relative to B12 itself. While the native function of CarH involves transcription regulation via AdoCbl Co(III)-carbon bond cleavage and β-hydride elimination to generate 4’,5’-didehydroadenosine, CarH*-catalyzed styrene alkylation proceeds via non-native oxidative addition and olefin addition coupled with a native-like β-hydride elimination. Mechanistic studies on this reaction echo findings from earlier studies on AdoCbl homolysis under strong cage conditions to suggest that CarH* can enable non-native radical chemistry with improved selectivity relative to B12 itself. These findings lay the groundwork for the development of B12-dependent enzymes as catalysts for a wide range of non-native transformations.

scholarly journals Cu/Pd-catalyzed borocarbonylative trifunctionalization of alkynes and allenes: synthesis of β-geminal-diboryl ketones

2021 ◽  
Author(s):  
Yang Yuan ◽  
Fu-Peng Wu ◽  
Anke Spannenberg ◽  
Xiao-Feng Wu
Keyword(s):  
Organic Synthesis ◽  
Functional Group ◽  
Building Blocks ◽  
Mechanistic Studies ◽  
Efficient Strategy ◽  
New Class ◽  
Reaction Proceeds

AbstractFunctionalized bisboryl compounds have recently emerged as a new class of synthetically useful building blocks in organic synthesis. Herein, we report an efficient strategy to synthesize β-geminal-diboryl ketones enabled by a Cu/Pd-catalyzed borocarbonylative trifunctionalization of readily available alkynes and allenes. This reaction promises to be a useful method for the synthesis of functionalized β-geminal-diboryl ketones with broad functional group tolerance. Mechanistic studies suggest that the reaction proceeds through borocarbonylation/hydroboration cascade of both alkynes and allenes.

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