Scandium-Catalyzed Skeleton Conversion of Lathyrane to Lathyranone-Type Diterpenes.

Naturally occurring 1(15 → 14)-lathyrane rearrangement-type diterpene lathyranone A () was prepared from lathyrane-type factor L () via an efficient Sc(OTf)/EtNH-catalyzed α-ketol rearrangement, which was also suitable for the synthesis of lathyranones and . This skeletal conversion strategy had the characteristic of biogenetically patterned synthesis and provided a convenient method for accessing naturally rare functionalized lathyranones from lathyranes. Moreover, the absolute configuration of the lathyranone skeleton was confirmed for the first time by the X-ray diffraction of .