ChemInform Abstract: Claisen Rearrangement of Z- and E-4,5-Dimethoxy-2-prenyloxycinnamic Acids: Formation of Scopoletin, Suberosin and 3-Prenylscoparone.

ChemInform Abstract

In order to prepare the methyl ether of obliquetin, scoparone (I) is transformed to the Z-acid (III) which is subjected to Claisen rearrangement. However, no formation of the desired ether is observed and scopoletin (IV) and suberosin (V) are identified instead. Compound (VI), when subjected to conditions A), yields the 3-prenyl derivative (VII). These results provide a simple method for preparing3-prenylated coumarins from coumarins whose 6- and 8-positions are either hindered or substituted.