A Formal Synthesis of Vinigrol

摘要

In 1987, Hashimoto and co-workers isolated an unprecedented compact diterpene, vinigrol (1, Scheme 1), from the fungal strain Virgaria nigra F-5408, found at the foot of Mount Aso in the Kumamoto Prefecture in Japan. The relative stereochemistry of the natural product was established by NMR and X-ray crystallographic analysis of the oxidized derivative 2. Its tricyclic core is comprised of a cis-fused [4.4.0] system with a four-carbon bridge between C1 and C5 and features eight contiguous stereocenters. The rare boat half chair conformation of the eight-membered ring (highlighted in Scheme 1 in bold) makes vinigrol a unique structure among diterpenoids.