DBU-mediated [4 + 2] annulation of β,γ-unsaturated α-keto esters and p-quinone methides has been developed. Under mild conditions, the reaction afforded polysubstituted 4-aryl chromans and tetrahydroquinolines as single diastereoisomer in high yields (up to 91% yield) at room temperature.

中文翻译：

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β，γ-不饱和α-酮酸酯和对醌甲基化物的非对映选择性[4 + 2]高环化：多取代的4-芳基色氨酸和四氢喹啉的制备方法

已经开发了DBU介导的[4 + 2]的β，γ-不饱和α-酮酯和对醌甲基化物的环化。在温和的条件下，该反应在室温下以高收率（高达91％的收率）提供了多取代的4-芳基苯并二氢吡喃和四氢喹啉，为单一的非对映异构体。