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Synthesis of Tetrasubstituted Furan Derivatives by Condensation of 1,3‐Diketones with Cyclic α‐Hydroxy‐β‐oxo Esters
Author(s) -
Schickmous Barhiem,
Christoffers Jens
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402388
Subject(s) - chemistry , alicyclic compound , furan , decarboxylation , acetylacetone , cycloalkane , substituent , organic chemistry , medicinal chemistry , ring (chemistry) , condensation reaction , catalysis
Tetrasubstituted 3‐acylfuran derivatives were obtained by condensation of acetylacetone with alicyclic and heterocyclic α‐hydroxy‐β‐oxo esters under acidic conditions [0.1 equiv. cerium(III) salt in AcOH]. With [ b ]‐annulated 4‐acyl‐3‐hydroxy‐5‐methylfuran‐2‐carboxylates as common intermediates, the reaction proceeded along different pathways depending on the starting materials used: Alicyclic α‐hydroxy‐β‐oxo esters gave cycloalkane‐annulated furans as products. The ester group was lost after saponification and decarboxylation at elevated temperature. A thiopyrano[3,4‐ b ]‐annulated 2 H ‐furan was obtained when starting from a tetrahydrothiopyranone derivative. With piperidones or a tetrahydropyranone as starting materials, the heterocyclic six‐membered ring was cleaved in a retro‐Mannich type reaction and one carbon atom was lost. 4‐Acetyl‐5‐methylfuran‐2‐carboxylates with a 2‐amino or 2‐hydroxyethyl substituent in the 3‐position are obtained in these cases.