- The Synthesis of (+/-)-Coronafacic Acid by a Tandem Wessely Oxidation-Diels-Alder Reaction Sequence
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(+/-)-Coronafacic acid (9) has been synthesized from ethyl 5-(4-ethyl-2-hydroxyphenyl)pent-2-enoate (4) via a tandem Wessely oxidation-Diels-Alder reaction sequence.
- Bhamare, N. K.,Granger, Thierry,Macas, T. S.,Yates, Peter
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- Tandem Wessely oxidation and intramolecular Diels-Alder reactions. IV. The synthesis of (+/-)-coronafacic acid
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Ethyl E-5-(4-ethyl-2-hydroxyphenyl)-2-pentenoate (7), prepared in four steps from m-ethylphenol (9), was converted via Wessely oxidation with lead tetraacetate followed by intramolecular Diels-Alder reaction in boiling xylene to ethyl 1-acetyloxy-6-ethyl-2,3,3a,4,5,7a-hexahydro-8-oxo-1,5-methano-1H-indene-anti-4-carboxylate (16).Hydrogenation of 16 followed by mild hydrolysis gave ethyl 6-ethyloctahydro-1-hydroxy-8-oxo-1,5-methano-1H-indene-anti-4-carboxylate (24), which on oxidation with periodate gave 4-(ethoxycarbonyl)-6-ethyloctahydro-1-oxo-1H-indene-5-carboxylic acid (26).Oxidative decarboxylation of this gave a mixture of ethyl 6-ethyl-2,3,3a,6,7,7a-hexahydro-1-oxo-1H-indene-4-carboxylate (31) and ethyl 6-ethyl-2,3,3a,4,7,7a-hexahydro-1-oxo-1H-indene-4-carboxylate (32); the latter was converted to the former by ethanolic sodium ethoxide.Hydrolysis of 31 with hot hydrochloric acid gave (+/-)-coronafacic acid (4).
- Yates, Peter,Bhamare, N. K.,Granger, Thierry,Macas, T. S.
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p. 995 - 1001
(2007/10/02)
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