Synthesis of Naphthopyrans via Formal (3+3)-Annulation of Propargylic (Aza)-<i>para</i>-Quinone Methides with Naphthols
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
Abstract
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.
Topics & Concepts
AnnulationChemistryQuinoneConjugateCombinatorial chemistryOrganic chemistryCatalysisMathematicsMathematical analysisSynthesis of Indole DerivativesSulfur-Based Synthesis TechniquesMulticomponent Synthesis of Heterocycles