Gallium(III)-Catalyzed Cycloisomerization Approach to the Diterpenoid Alkaloids: Construction of the Core Structure for the Hetidines and Hetisines


  • The work was supported by a grant from the NIH USA (NIGMS RO1 084906). F. de J.C. is grateful to the NIH USA for a graduate award (F31 GM089139) and D.L. thanks the FQNRT Canada for a postdoctoral fellowship. R.S. is a Camille-Dreyfus Teacher Scholar, an Alfred P. Sloan Fellow, and acknowledges unrestricted support from Abbott, Eli Lilly, Astra Zeneca, and Aldrich.


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A versatile core structure has been prepared that should provide a foundation for the syntheses of the hetidine- and hetisine-type diterpenoid alkaloids. The synthesis of the caged polycyclic core structure, which features nine contiguous stereocenters, utilizes a GaIII-catalyzed cycloisomerization of an alkynyl indene as well as a Michael/aldol sequence to build the bicyclo[2.2.2] framework.