Mercuric Triflate-TMU Catalyzed Hydration of Terminal Alkyne to give Methyl Ketone under Mild Conditions

Water and zirconium(IV) as catalyst were found to be effective in the transformation of terminal aromatic alkyne to aromatic methyl ketone in the microwave. This terminal alkyne hydration reaction proceeded in excellent yield with Zr(cp)2Cl2. The reaction was moved efficiently in presence of electron donating or electron withdrawing substituent on aromatic ring. An eco-friendly synthesis of aldehyde by oxidative cleavage of nitroalkene was developed with Zr(cp)2Cl2 catalyst and water in microwave.

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

Synlett ◽

10.1055/s-0037-1611780 ◽

2019 ◽

Vol 30 (08) ◽

pp. 932-938 ◽

Cited By ~ 4

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.

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Effect of the ortho-hydroxy group of salicylaldehyde in the A3 coupling reaction: A metal-catalyst-free synthesis of propargylamine

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.13.53 ◽

2017 ◽

Vol 13 ◽

pp. 552-557 ◽

Cited By ~ 9

Author(s):

Sujit Ghosh ◽

Kinkar Biswas ◽

Suchandra Bhattacharya ◽

Pranab Ghosh ◽

Basudeb Basu

Keyword(s):

Green Chemistry ◽

Hydroxy Group ◽

Building Block ◽

Coupling Reaction ◽

Metal Catalyst ◽

Terminal Alkyne ◽

Mild Conditions ◽

Metal Catalyzed ◽

A3 Coupling

The synthesis of propargylamines via A3 coupling mostly under metal-catalyzed procedures is well known. This work invented an unprecedented effect of salicylaldehyde, one of the A3 coupling partners, which could lead to the formation of propargylamine, an important pharmaceutical building block, in the absence of any metal catalyst and under mild conditions. The role of the hydroxy group in ortho position of salicylaldehyde has been explored, which presumably activates the Csp–H bond of the terminal alkyne leading to the formation of propargylamines in good to excellent yields, thus negating the function of the metal catalyst. This observation is hitherto unknown, tested for a variety of salicylaldehyde, amine and acetylene, established as a general protocol, and is believed to be of interest for synthetic chemists from green chemistry.

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Kajian Regiokimia Markovnikov Melalui Mekanisme Reaksi Hidrasi Alkuna Terminal pada Etinilestradiol dengan Katalis FeCl3

Fullerene Journal of Chemistry ◽

10.37033/fjc.v6i1.263 ◽

2021 ◽

Vol 6 (1) ◽

pp. 39

Author(s):

Hotma Rotua Br. Simbolon ◽

Rymond Jusuf Rumampuk ◽

Anderson Arnold Aloanis

Keyword(s):

Nuclear Magnetic Resonance ◽

Reaction Mechanism ◽

Reaction Rate ◽

Methyl Ketone ◽

Proton Nuclear Magnetic Resonance ◽

Hydration Reaction ◽

Terminal Alkynes ◽

Terminal Alkyne ◽

Reaction Products ◽

Reaction Conditions

The terminal alkynes hydration reaction on 17α-ethynylestradiol (1) with FeCl3 catalyst mediated by dichloromethane aims to determine the reaction products produced and to conduct a Markovnikov regiochemistry study through the proposed reaction mechanism. The reaction conditions were carried out at a temperature of 50oC (48 hours) and 60oC (19 hours), the separation of the reaction properties was carried out using Gravity Column Chromatography, and the reaction products were identification using by Proton Nuclear Magnetic Resonance (1H-NMR). Here we describe the process of the FeCl3 catalyst forming a coordination complex with the terminal alkyne, which is then addition by nucleophilic water following Markovnikov's regiochemistry to finally produce the product of a methyl ketone, 17α-acetylestradiol (6). The catalyst used is a cationic ligand coordinate, where Fe3+ is a Lewis acid and Cl3- acts as a ligand. The dichloromethane solvent used can also increase the reaction rate.

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The Diorgano Dichalcogenides Addition to Benzyne under Mild Conditions

10.3390/ecsoc-11-01344 ◽

2007 ◽

Author(s):

Fabiano Toledo ◽

Henrique Marques ◽

João Comasseto ◽

Cristiano Raminelli

Keyword(s):

Mild Conditions

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Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

10.26434/chemrxiv.11742687 ◽

2020 ◽

Author(s):

Shubham Deolka ◽

Orestes Rivada Wheelaghan ◽

Sandra Aristizábal ◽

Robert Fayzullin ◽

Shrinwantu Pal ◽

...

Keyword(s):

Alkyl Group ◽

Bond Activation ◽

Bond Cleavage ◽

Terminal Alkyne ◽

Alkyl Aryl ◽

Metal Metal ◽

The Stability ◽

Selective Formation ◽

Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

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Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

10.26434/chemrxiv.11145098 ◽

2019 ◽

Author(s):

Raghu Nath Dhital ◽

keigo nomura ◽

Yoshinori Sato ◽

Setsiri Haesuwannakij ◽

Masahiro Ehara ◽

...

Keyword(s):

Activation Energy ◽

Low Temperature ◽

Dft Calculations ◽

Bond Activation ◽

Mild Conditions ◽

Selective Transformation ◽

Rate Determining Step ◽

Highly Active ◽

Harsh Conditions ◽

Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the beta-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

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Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

10.26434/chemrxiv.12052647.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Birgit Meindl ◽

Katharina Pfennigbauer ◽

Berthold Stöger ◽

Martin Heeney ◽

Florian Glöcklhofer

Keyword(s):

Wittig Reaction ◽

Condensation Reaction ◽

Synthetic Methods ◽

Anthracene Derivative ◽

Double Ring ◽

Mild Conditions ◽

Wide Range ◽

Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.

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SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

10.26434/chemrxiv.12026811.v1 ◽

2020 ◽

Author(s):

Subham Mahapatra ◽

Cristian P. Woroch ◽

Todd W. Butler ◽

Sabrina N. Carneiro ◽

Sabrina C. Kwan ◽

...

Keyword(s):

Room Temperature ◽

Medicinal Chemistry ◽

Mild Conditions ◽

Broad Array

A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds.

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