Synthesis of Naphthopyrans via Formal (3+3)-Annulation of Propargylic (Aza)- para -Quinone Methides with Naphthols

作者：Xiang‐Zhi Zhang, Bao Qiong Li, Zong‐Wang Qiu, Ai‐Jun Ma, Jin‐Bao Peng, Ji‐Yuan Du, Na Feng, Xue-Tao Xu, Han‐Peng Pan · 发表于：The Journal of Organic Chemistry · 年份：2020 · DOI：10.1021/acs.joc.0c01791 · 被引用次数：24 · 研究领域：Synthesis of Indole Derivatives、Sulfur-Based Synthesis Techniques、Multicomponent Synthesis of Heterocycles

Herein, we report an efficient Brønsted acid-catalyzed formal (3+3)-annulation of (aza)- para -quinone methides generated in situ from propargylic alcohols with naphthol derivatives, which involves a 1,8-conjugate addition/6-endo annulation process. This protocol provides an effective method for preparing important functionalized pyranocoumarins under mild conditions.