Total synthesis of (-)-panduratin D.

Herein, an enantioselective total synthesis of (-)-panduratin D, a novel secondary metabolite against human pancreatic PANC-1 cancer cell, from commercially available 3-methoxyphenol is reported. The synthesis was completed in nine steps and the key features include Sonogashira coupling, anionic Snieckus-Fries rearrangement, directed ortho metalation, tandem Si → C Alkyl rearrangement/Claisen-Schmidt condensation, and chiral boron complex-promoted asymmetric Diels-Alder cycloaddition. These endeavors could facilitate the biological studies of (-)-panduratin D and its analogs.

From Carbamate to Chalcone: Consecutive Anionic Fries Rearrangement, Anionic Si → C Alkyl Rearrangement, and Claisen-Schmidt Condensation.

A highly efficient one-pot procedure was developed for the synthesis of various 2'-hydroxychalcones from phenyl diethylcarbamate, featuring consecutive Snieckus-Fries rearrangement, anionic Si → C alkyl rearrangement, and Claisen-Schmidt condensation in a single operation. The applicability of this protocol was demonstrated by the highly efficient synthesis of the anti-inflammatory natural product lonchocarpin. The mechanism insight is also provided.