Globostellatic acid

This olefination strategy has been used by Kobayashi to synthesize globostellatic acid analogs, an antiangiogenic triterpene derivative from the marine sponge Stelletta globostellata (Fig. 14) [57]. Thus ketone 44 is olefinated by ynolate to yield the tetrasubstituted olefin 45. 

Kotoku, N., Tamada, N., Hayashi, A., and Kobayashi, M. (2008) Synthesis of BC-ring model of globostellatic acid X methyl ester, an anti-angiogenic substance from marine sponge. Bioorg Med. Chem. Lett., 18, 3532-3535. 

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