A new approach has been developed for the synthesis of 8-substituted 2H-chromenes, featuring a novel cascade aromatic Claisen rearrangement/o-quinone methide formation/6π-electrocyclization. This new method was demonstrated with 28 examples tolerating different substitutions at alkenes, allylic and aromatic ring and with total syntheses of three 2H-chromene natural products.

中文翻译：

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级联Claisen重排/ ö -quinone甲基化物形成/ electrocyclization方法2个ħ -chromenes

已经开发出用于合成8-取代的2 H-色烯的新方法，其特征在于新颖的级联芳族克莱森重排/邻醌甲基化物形成/6π-电环化。28个实例可以耐受烯烃，烯丙基和芳环的不同取代，并可以合成三种2 H-色烯天然产物，从而证明了这种新方法。