Catalyst-Free Synthesis of Chromane-Type N,O-Acetals via Intramolecular Addition of Phenols to Enamines

Autor:	Kirill S. Korzhenko, Irina V. Melnikova, Dmitry V. Osipov, Irina A. Semenova, Yuri N. Klimochkin, Vitaly A. Osyanin
Rok vydání:	2020
Předmět:	Formamide chemistry.chemical_compound chemistry Cascade reaction Intramolecular force Organic Chemistry Chromane Amine gas treating Phenols Medicinal chemistry Catalysis
Zdroj:	Synthesis. 52:3604-3621
ISSN:	1437-210X 0039-7881
DOI:	10.1055/s-0040-1707209
Popis:	A new strategy to 2-aminochromanes through catalyst-free cascade reaction of 3-trifluoroacetyl-4H-chromenes and 4H-chromene-3-carbaldehydes with cyclic secondary amines is presented. The reaction proceeds through subsequent 1,4- and 1,2-additions of amine, bimolecular elimination of trifluoroacetamide or formamide, and 6-exo-trig cyclization. The latter stage is a very rare example of addition of phenols to enamines. The obtained semicyclic N,O-acetals were applied as useful precursors for the synthesis of other chromanes.
Databáze:	OpenAIRE
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