Total Synthesis of (-)-Gardmultimine A.
Peiqi ChenHesi YangHao ZhangWei ChenZheng ZhangJing ZhangHuilin LiXiaolei WangXingang XieXuegong ShePublished in: Organic letters (2020)
The first total synthesis of Gardneria oxindole alkaloid (-)-gardmultimine A has been achieved in 19 steps from d-tryptophan in a fully stereocontrolled manner. This synthesis features (1) an Ir-catalyzed regioselective C-H borylation/oxidation sequence to introduce the C12 methoxyl group, (2) a stereocontrolled oxidative rearrangement of indole to construct the spirooxindole motif, and (3) an Au(I)-catalyzed transannular Conia-ene-type 6-exo-dig cyclization to establish the azabicyclo[2.2.2]octane skeleton and the exocyclic E-alkene with exclusive stereoselectivity.