scholarly journals C-H Functionalization Reactions of Unprotected N-Heterocycles by Gold Catalyzed Carbene Transfer

2020 ◽  
Author(s):  
Sripati Jana ◽  
Claire Empel ◽  
Chao Pei ◽  
Polina Aseeva ◽  
Thanh Vinh Nguyen ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Functional Groups ◽  
Gold Catalyst ◽  
Protecting Groups ◽  
Transfer Reactions ◽  
Mechanistic Studies ◽  
Economic Strategies ◽  
Carbene Transfer ◽  
Functionalization Reaction

<p>The C-H functionalization reaction of N-heterocycles with unprotected N-H group is one of the most step-economic strategies to introduce functional groups without the need of installation and removal of protecting groups. Despite recent significant advances in C-H functionalization chemistry, this strategy remains unsatisfactorily developed. In this report, we disclose a simple and straightforward protocol to allow for the selective C-H functionalization of unprotected double benzannellated N-heterocycles via gold catalyzed carbene transfer reactions (29 examples, up to 86% yield). The scope of the reaction can also be expanded to the corresponding protected heterocycles (37 examples, up to 98% yield), further demonstrating the generality of this method. Mechanistic studies by DFT calculations underpin the importance of the gold catalyst and reveal that the selectivity of this reaction is driven by trace amounts of water present in the reaction mixture.</p>

scholarly journals C-H Functionalization Reactions of Unprotected N-Heterocycles by Gold Catalyzed Carbene Transfer

2020 ◽  
Author(s):  
Sripati Jana ◽  
Claire Empel ◽  
Chao Pei ◽  
Polina Aseeva ◽  
Thanh Vinh Nguyen ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Functional Groups ◽  
Gold Catalyst ◽  
Protecting Groups ◽  
Transfer Reactions ◽  
Mechanistic Studies ◽  
Economic Strategies ◽  
Carbene Transfer ◽  
Functionalization Reaction

<p>The C-H functionalization reaction of N-heterocycles with unprotected N-H group is one of the most step-economic strategies to introduce functional groups without the need of installation and removal of protecting groups. Despite recent significant advances in C-H functionalization chemistry, this strategy remains unsatisfactorily developed. In this report, we disclose a simple and straightforward protocol to allow for the selective C-H functionalization of unprotected double benzannellated N-heterocycles via gold catalyzed carbene transfer reactions (29 examples, up to 86% yield). The scope of the reaction can also be expanded to the corresponding protected heterocycles (37 examples, up to 98% yield), further demonstrating the generality of this method. Mechanistic studies by DFT calculations underpin the importance of the gold catalyst and reveal that the selectivity of this reaction is driven by trace amounts of water present in the reaction mixture.</p>

A Gold Catalyst for Carbene-Transfer Reactions from Ethyl Diazoacetate

2005 ◽  
Vol 44 (33) ◽  
pp. 5284-5288 ◽  
Author(s):  
Manuel R. Fructos ◽  
Tomás R. Belderrain ◽  
Pierre de Frémont ◽  
Natalie M. Scott ◽  
Steven P. Nolan ◽  
...  
Keyword(s):  
Gold Catalyst ◽  
Transfer Reactions ◽  
Ethyl Diazoacetate ◽  
Carbene Transfer

scholarly journals C-H Functionalization via Iron-Catalyzed Carbene-Transfer Reactions

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 880 ◽  
Author(s):  
Claire Empel ◽  
Sripati Jana ◽  
Rene M. Koenigs
Keyword(s):  
Functional Groups ◽  
Organic Molecules ◽  
Transfer Reactions ◽  
Iron Catalysts ◽  
Reaction Conditions ◽  
Carbene Complexes ◽  
Small Organic Molecules ◽  
Iron Heme ◽  
Over Time ◽  
Functionalization Reaction

The direct C-H functionalization reaction is one of the most efficient strategies by which to introduce new functional groups into small organic molecules. Over time, iron complexes have emerged as versatile catalysts for carbine-transfer reactions with diazoalkanes under mild and sustainable reaction conditions. In this review, we discuss the advances that have been made using iron catalysts to perform C-H functionalization reactions with diazoalkanes. We give an overview of early examples employing stoichiometric iron carbene complexes and continue with recent advances in the C-H functionalization of C(sp2)-H and C(sp3)-H bonds, concluding with the latest developments in enzymatic C-H functionalization reactions using iron-heme-containing enzymes.

A Gold Catalyst for Carbene-Transfer Reactions from Ethyl Diazoacetate

2005 ◽  
Vol 117 (33) ◽  
pp. 5418-5422 ◽  
Author(s):  
Manuel R. Fructos ◽  
Tomás R. Belderrain ◽  
Pierre de Frémont ◽  
Natalie M. Scott ◽  
Steven P. Nolan ◽  
...  
Keyword(s):  
Gold Catalyst ◽  
Transfer Reactions ◽  
Ethyl Diazoacetate ◽  
Carbene Transfer

Visible Light-Mediated Oxidative Debenzylation

2020 ◽  
Author(s):  
Cristian Cavedon ◽  
Eric T. Sletten ◽  
Amiera Madani ◽  
Olaf Niemeyer ◽  
Peter H. Seeberger ◽  
...  
Keyword(s):  
Reaction Time ◽  
Visible Light ◽  
Functional Groups ◽  
Continuous Flow ◽  
Protecting Groups ◽  
Benzyl Ether ◽  
Complex Molecules ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Harsh Conditions

Protecting groups are key in the synthesis of complex molecules such as carbohydrates to distinguish functional groups of similar reactivity. The harsh conditions required to cleave stable benzyl ether protective groups are not compatible with many other protective and functional groups. The mild, visible light-mediated debenzylation disclosed here renders benzyl ethers orthogonal protective groups. Key to success is the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as stoichiometric or catalytic photooxidant such that benzyl ethers can be cleaved in the presence of azides, alkenes, and alkynes. The reaction time for this transformation can be reduced from hours to minutes in continuous flow. <br>

Catalyst-Controlled Site-Selective N-H and C3-Arylation of Carba-zole via Carbene Transfer Reactions

2021 ◽  
Author(s):  
Sourav Sekhar Bera ◽  
Srishti Ballabh Bahukhandi ◽  
Claire Empel ◽  
Rene M Koenigs
Keyword(s):  
Transfer Reactions ◽  
Palladium Acetate ◽  
Direct Arylation ◽  
Carbene Transfer ◽  
A Site ◽  
Site Selective

A site-selective direct arylation reaction of carbazole and other N-heterocycles with diazo-naphthalen-2(1H)-ones has been developed. While Au(I)-NHC catalysts lead to selective C3-arylation, palladium acetate allows for selective N-H arylation, displaying...

Carbene transfer reactions between transition-metal ions

1999 ◽  
Vol 28 (5) ◽  
pp. 315-322 ◽  
Author(s):  
Shiuh-Tzung Liu ◽  
K. Rajender Reddy
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Transition Metal Ions ◽  
Transfer Reactions ◽  
Carbene Transfer

scholarly journals A combined experimental and theoretical study on the reactivity of nitrenes and nitrene radical anions

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Yujing Guo ◽  
Chao Pei ◽  
Rene M. Koenigs
Keyword(s):  
Radical Anion ◽  
Room Temperature ◽  
Theoretical Study ◽  
Transition Metal Catalysts ◽  
Transfer Reactions ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Nitrene Transfer ◽  
Triplet Nitrene ◽  
Nitrogen Bonds

AbstractNitrene transfer reactions represent one of the key reactions to rapidly construct new carbon-nitrogen bonds and typically require transition metal catalysts to control the reactivity of the pivotal nitrene intermediate. Herein, we report on the application of iminoiodinanes in amination reactions under visible light photochemical conditions. While a triplet nitrene can be accessed under catalyst-free conditions, the use of a suitable photosensitizer allows the access of a nitrene radical anion. Computational and mechanistic studies rationalize the access and reactivity of triplet nitrene and nitrene radical anion and allow the direct comparison of both amination reagents. We conclude with applications of both reagents in organic synthesis and showcase their reactivity in the reaction with olefins, which underline their markedly distinct reactivity. Both reagents can be accessed under mild reaction conditions at room temperature without the necessity to exclude moisture or air, which renders these metal-free, photochemical amination reactions highly practical.

Sign in / Sign up

Export Citation Format

Share Document