Synthesis of Indolizidine Derivatives Trifluoromethylated at Bridgehead Position via Acyl Iminium Ion Intermediates Derived from Ring-Chain Tautomerism of 5,5,5-Trifluoro-4-oxopentanoyl Arylethylamides

Heterocycles ◽  
1997 ◽  
Vol 44 (1) ◽  
pp. 227 ◽  
Author(s):  
Shoji Eguchi ◽  
Takashi Okano ◽  
Tsutomu Sakaida
Keyword(s):  
Iminium Ion ◽  
Bridgehead Position

scholarly journals Effect of Counterion Structure on Rates and Diastereoselectivities in α,β-Unsaturated Iminium-Ion Diels–Alder Reactions

2011 ◽  
Vol 13 (14) ◽  
pp. 3758-3761 ◽  
Author(s):  
David Marcoux ◽  
Pascal Bindschädler ◽  
Alexander W. H. Speed ◽  
Anna Chiu ◽  
Joseph E. Pero ◽  
...  
Keyword(s):  
Diels Alder ◽  
Iminium Ion

ChemInform Abstract: Enamine-Iminium Ion Nazarov Cyclization of α-Ketoenones.

ChemInform ◽  
2010 ◽  
Vol 41 (26) ◽  
pp. no-no
Author(s):  
William F. Bow ◽  
Ashok K. Basak ◽  
Anois Jolit ◽  
David A. Vicic ◽  
Marcus A. Tius
Keyword(s):  
Nazarov Cyclization ◽  
Iminium Ion

Iminium ion mediated cyclizations of 4-aryl-1,4-dihydropyridines. Bridging with acetals, carbonyls, and thiocarbonyls

1985 ◽  
Vol 50 (14) ◽  
pp. 2423-2427 ◽  
Author(s):  
George D. Hartman ◽  
Brian T. Phillips ◽  
Wasyl Halczenko
Keyword(s):  
Iminium Ion

scholarly journals General α-Amino 1,3,4-Oxadiazole Synthesis via Late-Stage Reductive Functionalization of Tertiary Amides and Lactams

2021 ◽  
Author(s):  
Daniel Matheau-Raven ◽  
Darren J. Dixon
Keyword(s):  
Carboxylic Acid ◽  
Late Stage ◽  
Coupling Reaction ◽  
Reductive Activation ◽  
Mild Conditions ◽  
Drug Molecules ◽  
Drug Conjugates ◽  
Iminium Ion ◽  
Tertiary Amides ◽  
Coupling Partner

An iridium-catalyzed reductive three-component coupling reaction for the synthesis of medicinally relevant α-amino 1,3,4-oxadiazoles from abundant tertiary amides or lactams, carboxylic acids, and (N-isocyanimino) triphenylphosphorane, is described. Proceeding under mild conditions using (<1 mol%) Vaska’s complex (IrCl(CO)(PPh<sub>3</sub>)<sub>2</sub>) and tetramethyldisiloxane to access the key reactive iminium ion intermediates, a broad range of structurally complex α-amino 1,3,4-oxadiazole architectures were efficiently accessed from diverse carboxylic acid feedstock coupling partners. Extension to α-amino heterodiazole synthesis was readily achieved by exchanging the carboxylic acid coupling partner for C-, S-, or N-centered Brønsted acids, and provided rapid and modular access to these desirable, yet difficult-to-access, heterocycles. Furthermore, the high chemoselectivity of the catalytic reductive activation step allowed the late-stage functionalization of 10 drug molecules, including the synthesis of novel heterodiazole-fused drug-drug conjugates.<br>

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