SYNTHETIC STUDY OF CARBOCYCLIC CORE OF CORTISTATIN A, AN ANTI-ANGIOGENIC STEROIDAL ALKALOID FROM MARINE SPONGE

摘要

Synthesis of carbocyclic core of cortistatin A (1), a novel anti-angiogenic steroidal alkaloid from Indonesian marine sponge, was investigated. Intramolecular Heck cyclization using substrate 18 achieved construction of 7-membered B-ring structure. The presence of steric hindrance around the reaction center was found to favor endo cyclization pathway in this substrate.