Studies directed toward synthesis of taepeenin D: construction of the C4 stereogenic center and the CD benzofuran rings

摘要

Taepeenin D is a meroterpenoid isolated from roots and stems of Caesalpinia crista, showing inhibitory activity of Hedgehog signaling pathway. Herein we report selective and short-step construction of two fragments of taepeenin D. First, we demonstrated alkoxy radical-mediated selective functionalization at C19 methyl group for construction of the C4 quaternary carbon stereogenic center. Second, the CD benzofuran rings were constructed in 6 short steps from decalone. The synthesis described herein is not only applicable to total synthesis, but also used for study of the structure-activity relationships of taepeenin D. (C) 2016 Elsevier Ltd. All rights reserved.