scholarly journals Photoinduced Deaminative Borylation of Unactivated Aromatic Amines Enhanced by CO2

2021 ◽  
Author(s):  
Akira Shiozuka ◽  
Kohei Sekine ◽  
Yoichiro Kuninobu
Keyword(s):  
Aromatic Amines ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Inhibitory Effect ◽  
Light Irradiation ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Stoichiometric Amount ◽  
Optimal Reaction

Herein, direct unactivated C-N borylation of aromatic amines by a photocatalyst was achieved under mild and metal-free conditions. The C-N borylation of aromatic amines with bis(pinacolato)diboron (B<sub>2</sub>pin<sub>2</sub>) proceeded in the presence of a pyrene catalyst under light irradiation (λ = 365 nm) <a>to afford desired borylated products</a> and aminoborane as a byproduct. The yield of borylated product improved under a CO<sub>2</sub> atmosphere. Reactions conducted in the presence of a stoichiometric amount of aminoborane under N<sub>2</sub> or CO<sub>2</sub> indicated that CO<sub>2</sub> reduced the inhibitory effect of aminoborane. Optimal reaction conditions were applied to a variety of aromatic amines. Mechanistic studies suggested that the C-N bond cleavage and C-B bond formation proceeded via a concerted pathway.

scholarly journals Photoinduced Deaminative Borylation of Unactivated Aromatic Amines Enhanced by CO2

2021 ◽  
Author(s):  
Akira Shiozuka ◽  
Kohei Sekine ◽  
Yoichiro Kuninobu
Keyword(s):  
Aromatic Amines ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Inhibitory Effect ◽  
Light Irradiation ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Stoichiometric Amount ◽  
Optimal Reaction

Herein, direct unactivated C-N borylation of aromatic amines by a photocatalyst was achieved under mild and metal-free conditions. The C-N borylation of aromatic amines with bis(pinacolato)diboron (B<sub>2</sub>pin<sub>2</sub>) proceeded in the presence of a pyrene catalyst under light irradiation (λ = 365 nm) <a>to afford desired borylated products</a> and aminoborane as a byproduct. The yield of borylated product improved under a CO<sub>2</sub> atmosphere. Reactions conducted in the presence of a stoichiometric amount of aminoborane under N<sub>2</sub> or CO<sub>2</sub> indicated that CO<sub>2</sub> reduced the inhibitory effect of aminoborane. Optimal reaction conditions were applied to a variety of aromatic amines. Mechanistic studies suggested that the C-N bond cleavage and C-B bond formation proceeded via a concerted pathway.

I2/TBHP-Promoted Approach to α-Keto Esters from Trifluoromethyl β-Diketones and Alcohols via C–C Bond Cleavage

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 2018-2023 ◽  
Author(s):  
Xiang Fang ◽  
Xueyan Yang ◽  
Tongle Shao ◽  
Jun Zhou ◽  
Chen Jin ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Oxidation Pathway ◽  
Keto Esters ◽  
Oxidative Coupling Reaction

A metal-free oxidative coupling reaction of trifluoromethyl β-diketones with alcohols for the synthesis of α-keto esters in good to excellent yields has been developed. Preliminary mechanistic studies suggest that an I2/TBHP promoted sequential iodination, C–C bond cleavage, C–O bond formation and oxidation pathway is involved in this reaction.

Oxidative C–C Bond Cleavage for the Synthesis of Aryl Carboxylic Acids from Aryl Alkyl Ketones

Synlett ◽  
2018 ◽  
Vol 29 (11) ◽  
pp. 1505-1509 ◽  
Author(s):  
Meichao Li ◽  
Zhenlu Shen ◽  
Liang Xu ◽  
Shengpeng Wang ◽  
Bajin Chen ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Bond Cleavage ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Optimal Reaction

A metal-free and one-pot two-step synthesis of aryl carboxylic acids from aryl alkyl ketones has been achieved. The reactions were performed with iodine as the catalyst, DMSO and TBHP as the oxidants. Under the optimal reaction conditions, a number of aryl alkyl ketones could be converted into their corresponding aryl carboxylic acids in good to excellent yields (up to 94%).

scholarly journals Nitrosonium ion catalysis: aerobic, metal-free cross-dehydrogenative carbon–heteroatom bond formation

2018 ◽  
Vol 54 (92) ◽  
pp. 13022-13025 ◽  
Author(s):  
Luis Bering ◽  
Laura D’Ottavio ◽  
Giedre Sirvinskaite ◽  
Andrey P. Antonchick
Keyword(s):  
Bond Formation ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Metal Free ◽  
Dehydrogenative Coupling ◽  
Nitrosonium Ion

Catalytic cross-dehydrogenative coupling of heteroarenes with thiophenols and phenothiazines has been developed under mild and environmentally benign reaction conditions.

scholarly journals Selective C-N σ Bond Cleavage in Azetidinyl Amides under Transition Metal-Free Conditions

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 459 ◽  
Author(s):  
Hengzhao Li ◽  
Zemin Lai ◽  
Adila Adijiang ◽  
Hongye Zhao ◽  
Jie An
Keyword(s):  
Electron Transfer ◽  
Transition Metal ◽  
Transfer Reaction ◽  
Bond Cleavage ◽  
Electron Transfer Reaction ◽  
Amide Bond ◽  
Single Electron Transfer ◽  
Reaction Conditions ◽  
Metal Free ◽  
Single Electron Transfer Reaction

Functionalization of amide bond via the cleavage of a non-carbonyl, C-N σ bond remains under-investigated. In this work, a transition-metal-free single-electron transfer reaction has been developed for the C-N σ bond cleavage of N-acylazetidines using the electride derived from sodium dispersions and 15-crown-5. Of note, less strained cyclic amides and acyclic amides are stable under the reaction conditions, which features the excellent chemoselectivity of the reaction. This method is amenable to a range of unhindered and sterically encumbered azetidinyl amides.

Photoinduced Oxidative Cross-Coupling for O–S Bond Formation: A Facile Synthesis of Alkyl Benzenesulfonates

Synlett ◽  
2017 ◽  
Vol 28 (13) ◽  
pp. 1558-1563 ◽  
Author(s):  
Aiwen Lei ◽  
Atul Singh ◽  
Hong Yi ◽  
Guoting Zhang ◽  
Changliang Bian ◽  
...  
Keyword(s):  
Visible Light ◽  
Bond Formation ◽  
Cross Coupling ◽  
Selective Synthesis ◽  
Mechanistic Studies ◽  
Facile Synthesis ◽  
Metal Free

We have developed a photoinduced oxidative cross-coupling of thiophenols with alcohols for O–S bond formation. The protocol uses visible light, a metal-free photocatalyst, and oxygen as the oxidant for the selective synthesis of alkyl benzenesulfonates; no ligand co-additive is necessary. Mechanistic studies suggested that the disulfide and alkyl benzenesulfinate are involved as intermediates and that the transformation proceeds by a radical pathway.

Deuterated Aryl Alkyl Ethers Synthesis via Nucleophilic Etherification of Aryl Alkyl Ethers and Thioethers with Deuterated Alcohols

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1809
Author(s):  
Shuai Li ◽  
Xia Wang ◽  
Xin-Ge Yang ◽  
Gui-Quan Yu ◽  
Xue-Qiang Wang
Keyword(s):  
Transition Metal ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Wide Range ◽  
Alkyl Ethers

A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.

Visible-light-induced dual C–C bond formation via selective C(sp3)–H bond cleavage: efficient access to alkylated oxindoles from activated alkenes and simple ethers under metal-free conditions

2017 ◽  
Vol 19 (7) ◽  
pp. 1732-1739 ◽  
Author(s):  
Dong Xia ◽  
Yang Li ◽  
Tao Miao ◽  
Pinhua Li ◽  
Lei Wang
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Metal Free ◽  
Efficient Access ◽  
Oxidative Difunctionalization

A visible-light-induced oxidative difunctionalization of activated alkenes with simple ethersviaselective C(sp3)–H bond cleavage and dual C–C bond formation was developed.

Rhodium(I)-Catalysed Aryl C–H Carboxylation of 2-Arylanilines with CO2

2019 ◽  
Author(s):  
yuzhen gao ◽  
Zhihua Cai ◽  
Shangda Li ◽  
Gang Li
Keyword(s):  
General Type ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Direct Conversion ◽  
Activation Process ◽  
Amino Group ◽  
Mechanistic Studies ◽  
Organometallic Reagent ◽  
Cleavage Step ◽  
Neutral Conditions

<b>An unprecedented amino-group assisted C–H carboxylation of 2-arylanilines with CO<sub>2</sub> under redox-neutral conditions using a Rhodium(I)-catalyst has been developed. This reaction was promoted by a phosphine ligand with <i>t</i>-BuOK as the base and did not require the use of an extra strong organometallic reagent. Notably, this protocol may involve an oxidative addition in the C–H bond cleavage step and is distinct from previous Rh(I) or Rh(II)-catalysed methods for C–H carboxylation with </b><b>CO<sub>2</sub> </b><b>mechanistically. It enabled an efficient direct conversion of a broad range of 2-(hetero)arylanilines including electron-deficient heteroarenes to various phenanthridinones, which could be further transformed to other synthetically useful compounds readily. Preliminary mechanistic studies were carried out and possible intermediates of the reaction were evaluated, which revealed that the Rh(I)-catalyst is essential for the C–H activation process, providing a promising general type of method for utilization of </b><b>CO<sub>2</sub></b><b> for C–C bond formation.</b><br>

Metal-free enaminone C-N bond cyanation for stereoselective synthesis of (E)- and (Z)-β-cyano enones

2021 ◽  
Author(s):  
Ting Liu ◽  
Jie-Ping Wan ◽  
Yunyun Liu
Keyword(s):  
Stereoselective Synthesis ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Practical Method ◽  
Efficient Synthesis ◽  
Metal Free

A highly practical method for C-CN bond formation by C-N bond cleavage on enaminones leading to the efficient synthesis of β-cyano enones is developed. The reactions take place efficiently to...

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