Stereoselective Synthesis of the A-Ring of Armatol A from a Bromo-substituted Chiral Building Block Based on Ireland-Claisen Rearrangement and Ring-Closing Olefin Metathesis
摘要:
The stereoselective synthesis of the A-ring of armatol A, a natural polycyclic ether triterpene from the red alga Chondria armata, was achieved in a non-biomimetic way. The synthesis employed Ireland-Claisen rearrangement of an ester, prepared from a bromo-substituted chiral building block, for the construction of C6 and C7 stereocenters and a relay ring-closing olefin metathesis for the seven-membered ring formation.