Synthesis of Ficusnotins, Rare 1,4-Diarylbutanoids Derived from Ficusnota, via Ruthenium-Catalyzed Conjugate Addition

Ficusnotins are natural biarylbutanoids isolated from leaves of Ficus nota, a plant that is traditionally used as an alternative medicine in Southeast Asia. In this work, a concise synthesis of ficusnotin E was accomplished via ruthenium-catalyzed conjugate addition of 3,4-dimethoxyphenylboronic acid to a benzylvinyl ketone. Additionally, the other related natural 1,4-diarylbutanes derived from Ficus nota, namely, ficusnotin B, C, and F, were readily synthesized by subsequent chemical modifications of ficusnotin E. This procedure provides a concise and versatile route for the synthesis of ficusnotins and their biarylbutanoid analogs.