Lysilactones A–C, three 6H-dibenzo[b,d]pyran-6-one glycosides from Lysimachia clethroides, total synthesis of Lysilactone A

Abstract

Three 6H-dibenzo[b,d]pyran-6-one glycosides named lysilactones A–C (1–3) were isolated from the aerial parts of Lysimachia clethroides. Their structures were elucidated using spectroscopic analysis and chemical evidence. This is the first report of 6H-dibenzo[b,d]pyran-6-one glycosides. Furthermore, we have finished a total synthesis of lysilactone A. The key step is a Suzuki coupling used for the construction of the central biaryl bond. Lysilactone A was prepared in eight steps starting from phloroglucinic acid and orcinol, where the longest linear sequence is seven steps.