Synthesis of linear coumarins via para-Claisen rearrangement of coumarate ester derivatives: total synthesis of suberosin, demethylsuberosin, and ostruthin
Abstract
Heating 2′-O-prenylated derivatives of 4′-O-benzyl methyl coumarates (3) furnishes the corresponding linear prenylated umbelliferones (1) directly via sequential para-Claisen rearrangement and relactonisation.