scholarly journals Synthesis of Stereodefined 1,1-Diborylalkenes via Copper-Catalyzed Diboration of Terminal Alkynes

2020 ◽  
Author(s):  
Yang Gao ◽  
Zhong-Qian Wu ◽  
Keary Engle
Keyword(s):  
Functional Group ◽  
Aryl Halides ◽  
Terminal Alkynes ◽  
Mild Conditions ◽  
Tandem Process ◽  
Trisubstituted Alkenes

A copper-catalyzed method for the <i>E</i>-selective 1,1-diboration of terminal alkynes is described. The tandem process involves sequential dehydrogenative borylation of the alkyne substrate with HBdan (HBdan = 1,8-diaminonaphthalatoborane), followed by hydroboration with HBpin (HBpin = pinacolborane). This method proceeds efficiently under mild conditions, furnishing 1,1-diborylalkenes with excellent stereoselectivity and broad functional-group tolerance. Taking advantage of the different reactivities of the two boryl moieties, the products can then be employed in stepwise cross-couplings with aryl halides for the stereocontrolled construction of trisubstituted alkenes.

scholarly journals Synthesis of Stereodefined 1,1-Diborylalkenes via Copper-Catalyzed Diboration of Terminal Alkynes

2020 ◽  
Author(s):  
Yang Gao ◽  
Zhong-Qian Wu ◽  
Keary Engle
Keyword(s):  
Functional Group ◽  
Aryl Halides ◽  
Terminal Alkynes ◽  
Mild Conditions ◽  
Tandem Process ◽  
Trisubstituted Alkenes

A copper-catalyzed method for the <i>E</i>-selective 1,1-diboration of terminal alkynes is described. The tandem process involves sequential dehydrogenative borylation of the alkyne substrate with HBdan (HBdan = 1,8-diaminonaphthalatoborane), followed by hydroboration with HBpin (HBpin = pinacolborane). This method proceeds efficiently under mild conditions, furnishing 1,1-diborylalkenes with excellent stereoselectivity and broad functional-group tolerance. Taking advantage of the different reactivities of the two boryl moieties, the products can then be employed in stepwise cross-couplings with aryl halides for the stereocontrolled construction of trisubstituted alkenes.

scholarly journals Homocoupling of terminal alkynes catalyzed by CuCl under solvent-free conditions

2021 ◽  
pp. 174751982110325
Author(s):  
Yan Xiao ◽  
Jiyu Gao ◽  
Peng Chen ◽  
Guangliang Chen ◽  
Zicheng Li ◽  
...  
Keyword(s):  
Functional Group ◽  
Reaction Times ◽  
Environmentally Friendly ◽  
Solvent Free ◽  
Copper Salt ◽  
Terminal Alkynes ◽  
Mild Conditions ◽  
Solvent Free Conditions ◽  
Environmentally Friendly Process

A series of symmetrical 1,4-disubstituted buta-1,3-diynes is prepared with excellent yields (up to 95%) through homocoupling of terminal alkynes catalyzed by a copper salt under solvent-free conditions. This method provides an environmentally friendly process to prepare 1,3-diynes in short reaction times under mild conditions. Furthermore, the method is suitable for a wide substrate scope and has excellent functional group compatibility. The reaction can also be scaled up to gram level.

Copper(II)-Catalyzed C–N Coupling of Aryl Halides and N-Nucleophiles Promoted by Quebrachitol or Diethylene Glycol

Synlett ◽  
2019 ◽  
Vol 30 (19) ◽  
pp. 2161-2168
Author(s):  
Fangyu Du ◽  
Qifan Zhou ◽  
Yang Fu ◽  
Yuanguang Chen ◽  
Ying Wu ◽  
...  
Keyword(s):  
Diethylene Glycol ◽  
Functional Group ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Mild Conditions ◽  
Natural Ligand ◽  
Highly Effective ◽  
High Yields

Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-arylation of various amines and related aryl halides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C–N coupling reactions proceed under mild conditions and exhibit good functional group tolerance.

Acetic Acid-Promoted Rhodium(III)-Catalyzed Hydroarylation of Terminal Alkynes

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 932-938 ◽  
Author(s):  
Chang-Lin Duan ◽  
Xing-Yu Liu ◽  
Yun-Xuan Tan ◽  
Rui Ding ◽  
Shiping Yang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Functional Group ◽  
Bond Activation ◽  
Side Reactions ◽  
Terminal Alkynes ◽  
Terminal Alkyne ◽  
Mechanistic Studies ◽  
Mild Conditions ◽  
Reaction Proceeds

Rhodium(III)-catalyzed hydroarylation of terminal alkynes has not previously been achieved because of the inevitable oligomerization and other side reactions. Here, we report a novel Cp*Rh(III)-catalyzed hydroarylation of terminal alkynes in acetic acid as solvent to facilitate the C–H bond activation and subsequent transformations. This reaction proceeds under mild conditions, providing an effective approach to the synthesis of alkenylated heterocycles in high to excellent yields (31–99%) with a broad substrate scope (37 examples) and good functional-group compatibility. In this transformation, the loading of the alkyne can be reduced to 1.2 equivalents, which indicates the significant role of HOAc in lowering the reaction temperature and suppressing the oligomerization of the terminal alkyne. Preliminary mechanistic studies are also presented.

scholarly journals Nickel-catalyzed electrochemical carboxylation of unactivated aryl and alkyl halides with CO2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guo-Quan Sun ◽  
Wei Zhang ◽  
Li-Li Liao ◽  
Li Li ◽  
Zi-Hao Nie ◽  
...  
Keyword(s):  
Catalytic System ◽  
Functional Group ◽  
Alkyl Halides ◽  
Aryl Halides ◽  
Aryl Chlorides ◽  
Mild Conditions ◽  
Aryl Bromides ◽  
Alkyl Bromides ◽  
Pseudo Halides ◽  
Electrochemical Carboxylation

AbstractElectrochemical catalytic reductive cross couplings are powerful and sustainable methods to construct C−C bonds by using electron as the clean reductant. However, activated substrates are used in most cases. Herein, we report a general and practical electro-reductive Ni-catalytic system, realizing the electrocatalytic carboxylation of unactivated aryl chlorides and alkyl bromides with CO2. A variety of unactivated aryl bromides, iodides and sulfonates can also undergo such a reaction smoothly. Notably, we also realize the catalytic electrochemical carboxylation of aryl (pseudo)halides with CO2 avoiding the use of sacrificial electrodes. Moreover, this sustainable and economic strategy with electron as the clean reductant features mild conditions, inexpensive catalyst, safe and cheap electrodes, good functional group tolerance and broad substrate scope. Mechanistic investigations indicate that the reaction might proceed via oxidative addition of aryl halides to Ni(0) complex, the reduction of aryl-Ni(II) adduct to the Ni(I) species and following carboxylation with CO2.

Chiral Mn(III) Salen Complex Immobilized on CuFe2O4@SiO2-NH2 NPs: A Cheap and Efficient Catalyst for N-arylation of Aryl Halides and Phenylboronic Acid Under Mild Conditions

2020 ◽  
Vol 17 (11) ◽  
pp. 857-863
Author(s):  
Mohammad Ali Nasseri ◽  
Seyyedeh Ameneh Alavi ◽  
Milad Kazemnejadi ◽  
Ali Allahresani
Keyword(s):  
Phenylboronic Acid ◽  
Significant Loss ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Efficient Catalyst ◽  
Aryl Chlorides ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Salen Complex ◽  
Ft Ir

A convenient and efficient chiral CuFe2O4@SiO2-Mn(III) Ch.salen nanocatalyst has been developed for the C-N cross-coupling reactions of aryl halides/ phenylboronic acid with N-heterocyclic compounds in water and/or DMSO under mild conditions. The catalyst could be applied for the N-arylation of a variety of nitrogen-containing heterocycles with aryl chlorides, bromides, iodides and phenylboronic acid under mild conditions. Moderate to good yields were achieved for all substrates. The structure of catalyst was characterized using various techniques including FT-IR, FE-SEM, EDX, XRD, TEM and TGA. The catalyst can be simply recovered and reused for several times without significant loss of activity.

The Azidosulfonylation of Terminal Alkynes Leading to β-azidovinyl Sulfones

2021 ◽  
Author(s):  
Long Zheng ◽  
Zhanjing Wang ◽  
Chen Li ◽  
Yong Wu ◽  
Zhaohong Liu ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Functional Group ◽  
High Yield ◽  
Terminal Alkynes

We reported herein the first example of N3 radical-mediated azidosulfonylation of alkynes, affording the β-azidovinyl sulfone products in broad substrate scope, excellent functional group compatibility, and high yield. DFT calculations...

Asymmetric Synthesis of α-Alkylated γ-Lactam via Nickel/8-Quinim-Catalyzed Reductive Alkyl-Carbamoylation of Unactivated Alkene

Synlett ◽  
2021 ◽  
Author(s):  
Xianqing Wu ◽  
Mohini Shrestha ◽  
Yifeng Chen
Keyword(s):  
Functional Group ◽  
Enantioselective Synthesis ◽  
Chiral Auxiliary ◽  
Alkyl Iodide ◽  
General Strategy ◽  
Chemical Bonds ◽  
Mild Conditions ◽  
Chiral Carbon ◽  
Enantioselective Reaction ◽  
Metal Catalyzed

AbstractChiral-auxiliary-mediated synthesis represents the most frequently used synthetic tool for the induction of chirality on α-position of γ-lactams in organic synthesis. However, the general strategy requires the stoichiometric use of chiral reagents with multiple manipulation steps. Transition-metal-catalyzed asymmetric alkene dicarbofunctionalization using readily available substrates under mild conditions allows the simultaneous construction of two vicinal chemical bonds and a chiral carbon center, hence, gain expedient access to chiral heterocycles. Herein, we disclose a Ni-catalyzed enantioselective reaction of 3-butenyl carbamoyl chloride and primary alkyl iodide enabled by a newly designed chiral 8-quinoline imidazoline ligand (8-Quinim). This protocol features broad functional group tolerance and high enantioselectivities, achieving unprecedented synthesis of chiral nonaromatic heterocycles via catalytic reductive protocol.1 Introduction2 Development of 8-Quinim Ligand3 Nickel/8-Quinim-Catalyzed Enantioselective Synthesis of Chiral α-Alkylated γ-Lactam4 Conclusion and Outlook

Rh (III)-catalyzed C(sp2)-H functionalization/cyclization cascade of N-carboxamide indole and iodonium reagent for access to indoloquinazolinone derivatives

2021 ◽  
Author(s):  
Zhi-Peng Han ◽  
Mengmeng Xu ◽  
Rui-Ying Zhang ◽  
Xiao-Ping Xu ◽  
Shun-Jun Ji
Keyword(s):  
Functional Group ◽  
Mild Conditions

Rhodium-catalyzed synthesis of indoloquinazoline from readily available hypervalent iodonium reagent and N-carboxamide indole was developed. The protocol features broad functional group tolerance, mild conditions, excellent yields and simple workup. Notably,...

Borates as a Traceless Activation Group for Intermolecular Alkylarylation of Ethylene through Photoredox/Nickel Dual Catalysis

Synlett ◽  
2020 ◽  
Author(s):  
Shengqing Zhu ◽  
Lingling Chu ◽  
Xiaoliang Feng ◽  
Lei Guo
Keyword(s):  
Functional Groups ◽  
Aryl Halides ◽  
Nickel Catalysis ◽  
Mild Conditions ◽  
Dual Catalysis

AbstractA formal ethylene alkylarylation reaction with aryl halides and alkyl oxalates enabled by synergistic photoredox/nickel catalysis is reported. This protocol takes advantage of borates as a traceless activation group, achieving the formal ethylene difunctionalized products via a catalytic three-component 1,2-alkylarylation of vinyl borate followed by a base-assisted deborylation process. The mild conditions allow for excellent functional groups compatibility and broad substrate scope.

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