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Reaction of α,β‐unsaturated acid chlorides with β‐diketones. Synthesis of 4,6,7,8‐tetrahydro‐2 H ‐1‐benzopyran‐2,5(3 H )‐diones
Author(s) -
Monroe Bruce M.
Publication year - 1969
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570060623
Subject(s) - chemistry , acryloyl chloride , chloride , enol , medicinal chemistry , cyclohexane , bicyclic molecule , organic chemistry , catalysis , acrylate , monomer , polymer
Reaction of an α,β‐unsaturated acid chloride with the anion of 5,5‐dimethyl‐1,3‐cyclohexane‐dione ( 2 ) gives either the enol ester ( 4 ) or a cyclized product ( 5 ), depending upon the reaction conditions. When the acid chloride is in excess, the ester is obtained. When the anion is in excess and the acid chloride is acryloyl or crotonyl, the cyclized product is obtained. A similar cyclized product ( 9 ) was formed from acryloyl chloride and an excess of the anion of 4‐hydroxy‐6‐methyl‐2‐pyrone ( 8 ).