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[摘要]:Two strategies were developed to prepare 8-hydroxyisocoumarins from substituted 3-ethoxycyclohex-2-en-1-ones. The key reactions in the first strategy were the cyclization of a 2-hydroxymethy1-3-ethynyl-cyclohex-2-en-1-one, followed by the aromatization of the resulting cyclohexenone-pyran intermediate. The second approach featured the reaction of 2-hydroxymethy1-3-vinyl-cyclohex-2-en-1-ones with DDQ to directly produce isocoumarins. This new two-step sequence was used to prepare oospolactone in 57% overall yield. |
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