Influence of Lewis Acids on the Diels–Alder Reaction. VI. Reaction of 2,5-Dimethyl- and 2,5-Diphenylfuran with Ethyl Propiolate
The AlCl3-promoted reactions of 2,5-dimethyl- and of 2,5-diphenylfuran with ethyl propiolate afford as major products ethyl 2,6-dimethyl-3-hydroxybenzoate (6a) and ethyl 3,5-diphenyl-2-hydroxybenzoate (8b), respectively. Also isolated from these reactions were ethyl 2,4-dimethyl-5-hydroxybenzoate (7a), ethyl 3,5-dimethyl-2-hydroxybenzoate (8a), ethyl 2,4-diphenyl-5-hydroxybenzoate (7b), and ethyl 2,6-diphenyl-3-hydroxybenzoate (6b). Minor by-products were trans ethyl 3-(2,5-dimethyl-3-furyl-acrylate (10) and ethyl 3-acetyl-2-(2,5-dimethyl-3-furyl)-5-methyl-cyclopenta-2,5-dienecarboxylate (11).
1971 ◽
Vol 49
(19)
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pp. 3152-3157
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2006 ◽
Vol 84
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pp. 1487-1503
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1981 ◽
Vol 112
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pp. 679-682
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