A strategically new approach to 9-substituted 2,3,4,9-tetrahydro-1H-xanthen-1-ones is described. The protocol includes TMG promoted, conjugate addition of cyclohexane-1,3-diones to 3-(diethoxyphosphoryl)coumarins and a domino transesterification-cyclodehydration reaction of the adducts obtained. Modification of the tetrahydroxanthenone at position 9 is reported for the first time.

中文翻译：

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新型9-取代的2,3,4,9-四氢-1 H-黄嘌呤-1-酮的简便合成

描述了一种策略上新颖的9-取代的2,3,4,9-四氢-1 H-黄嘌呤-1-酮的方法。该方案包括TMG促进的，将环己烷-1,3-二酮共轭添加到3-（二乙氧基磷酰基）香豆素中，以及获得的加合物的多米诺酯交换-环脱水反应。首次报道了在位置9对四氢黄酮的修饰。