| 内容提要: |
Discuss a total synthesis of articaes, total synthesis of (±)Corymine, the first total synthesis of the hexacyclic indole alkaloid (:)-corymine is described. Starting from the readily available N-protected tryptamine, the title compound was achieved in 21 steps in 3.4% overall yield. Key steps of the synthesis include: a) the addition of a malonate to a 3- bromooxindole to afford 3,3-disubstituted oxindole, b) the formation of a 12-membered cyclic enol ether by intramolecular O-propargylation, immediately followed by propargyl Claisen rearrangement to provide the a-allenyl ketone stereospecifically, c) DMDO oxidation to install a hydroxy group in a highly stereoselective manner, and d) the SmI2-mediated reductive C-O bond cleavage to remove the a-keto carboxyl group. |