NDLI: Cobalt‐Porphyrin‐Catalysed Intramolecular Ring‐Closing C−H Amination of Aliphatic Azides: A Nitrene‐Radical Approach to Saturated Heterocycles

Please wait, while we are loading the content...

Cobalt‐Porphyrin‐Catalysed Intramolecular Ring‐Closing C−H Amination of Aliphatic Azides: A Nitrene‐Radical Approach to Saturated Heterocycles

Content Provider	Semantic Scholar
Author	Kuijpers, Petrus F. Tiekink, Martijn J. Breukelaar, Willem B. Broere, Daniël L. J. Leest, Nicolaas P. Van Vlugt, Jarl Ivar Van Der Reek, Joost N. H. Bruin, Bas De
Copyright Year	2017
Abstract	Cobalt-porphyrin-catalysed intramolecular ring-closing C-H bond amination enables direct synthesis of various N-heterocycles from aliphatic azides. Pyrrolidines, oxazolidines, imidazolidines, isoindolines and tetrahydroisoquinoline can be obtained in good to excellent yields in a single reaction step with an air- and moisture-stable catalyst. Kinetic studies of the reaction in combination with DFT calculations reveal a metallo-radical-type mechanism involving rate-limiting azide activation to form the key cobalt(III)-nitrene radical intermediate. A subsequent low barrier intramolecular hydrogen-atom transfer from a benzylic C-H bond to the nitrene-radical intermediate followed by a radical rebound step leads to formation of the desired N-heterocyclic ring products. Kinetic isotope competition experiments are in agreement with a radical-type C-H bond-activation step (intramolecular KIE=7), which occurs after the rate-limiting azide activation step. The use of di-tert-butyldicarbonate (Boc2 O) significantly enhances the reaction rate by preventing competitive binding of the formed amine product. Under these conditions, the reaction shows clean first-order kinetics in both the [catalyst] and the [azide substrate], and is zero-order in [Boc2 O]. Modest enantioselectivities (29-46 % ee in the temperature range of 100-80 °C) could be achieved in the ring closure of (4-azidobutyl)benzene using a new chiral cobalt-porphyrin catalyst equipped with four (1S)-(-)-camphanic-ester groups.
Starting Page	7945
Ending Page	7952
Page Count	8
File Format	PDF HTM / HTML
DOI	10.1002/chem.201700358
PubMed reference number	28332743
Journal	Medline
Volume Number	23
Alternate Webpage(s)	https://pure.uva.nl/ws/files/22305617/Cobalt_S.pdf
Alternate Webpage(s)	https://pure.uva.nl/ws/files/22305615/Cobalt.pdf
Alternate Webpage(s)	https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/ae/d4/CHEM-23-7945.PMC5488222.pdf
Alternate Webpage(s)	https://doi.org/10.1002/chem.201700358
Journal	Chemistry
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Mechanistic Investigation of the Cobalt Porphyrin Catalyzed Intramolecular Ring-Closing CH Amination of Aliphatic Azides

intramolecular C – H amination of aliphatic azides by dual ruthenium and phosphine catalysis †

Enantioselective intramolecular C-H amination of aliphatic azides by dual ruthenium and phosphine catalysis.

Iron porphyrin catalysed light driven C-H bond amination and alkene aziridination with organic azides.

dihydrophenazines via Iron-Catalyzed Intramolecular Ring- Closing C‒H Amination

Porphyrin Cobalt(III) “Nitrene Radical” Reactivity; Hydrogen Atom Transfer from Ortho-YH Substituents to the Nitrene Moiety of Cobalt-Bound Aryl Nitrene Intermediates (Y = O, NH)

Asymmetric Radical C–H Amination for the Synthesis of Azoles

Catalytic C-H amination driven by intramolecular ligand-to-nitrene one-electron transfer through a rhodium(iii) centre.

Chemoselective intramolecular allylic C–H amination versus CC aziridination through Co(ii)-based metalloradical catalysis

Cobalt‐Porphyrin‐Catalysed Intramolecular Ring‐Closing C−H Amination of Aliphatic Azides: A Nitrene‐Radical Approach to Saturated Heterocycles

Similar Documents

Mechanistic Investigation of the Cobalt Porphyrin Catalyzed Intramolecular Ring-Closing CH Amination of Aliphatic Azides

intramolecular C – H amination of aliphatic azides by dual ruthenium and phosphine catalysis †

Enantioselective intramolecular C-H amination of aliphatic azides by dual ruthenium and phosphine catalysis.

Iron porphyrin catalysed light driven C-H bond amination and alkene aziridination with organic azides.

dihydrophenazines via Iron-Catalyzed Intramolecular Ring- Closing C‒H Amination

Porphyrin Cobalt(III) “Nitrene Radical” Reactivity; Hydrogen Atom Transfer from Ortho-YH Substituents to the Nitrene Moiety of Cobalt-Bound Aryl Nitrene Intermediates (Y = O, NH)

Asymmetric Radical C–H Amination for the Synthesis of Azoles

Catalytic C-H amination driven by intramolecular ligand-to-nitrene one-electron transfer through a rhodium(iii) centre.

Chemoselective intramolecular allylic C–H amination versus CC aziridination through Co(ii)-based metalloradical catalysis

Cobalt‐Porphyrin‐Catalysed Intramolecular Ring‐Closing C−H Amination of Aliphatic Azides: A Nitrene‐Radical Approach to Saturated Heterocycles