A catalytic asymmetric [4+2] cyclization of ortho‐quinone methides with homophthalic anhydrides in the presence of chiral squaramide‐tertiary amine has been established. This method provides dihydrocoumarin frameworks in excellent diastereoselectivities (all >95:5 dr) and high enantioselectivities (81%–98% ee). This reaction represents the first application of homophthalic anhydrides as 2C building blocks in catalytic asymmetric cyclizations. In addition, this approach not only provides a useful method for constructing enantioenriched dihydrocoumarin frameworks but also advances the chemistry of catalytic asymmetric cyclizations of ortho‐quinone methides.

中文翻译：

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均苯酐作为2C结构单元在邻苯醌甲甲烷催化不对称环化中的应用：二氢香豆素骨架的非对映和对映选择性结构

建立了在手性方酰胺-叔胺存在下，邻苯二甲酰甲烷与高邻苯二甲酸酐的催化不对称[4 + 2]环化反应。该方法提供了出色的非对映选择性（所有> 95：5 dr）和高对映选择性（81％–98％ee）的二氢香豆素骨架。该反应代表高邻苯二甲酸酐作为2C结构单元在催化不对称环化中的首次应用。此外，该方法不仅为构建对映体富集的二氢香豆素骨架提供了一种有用的方法，而且还促进了邻醌甲基化物的催化不对称环化的化学反应。