A Concise and Versatile Double-Cyclization Strategy for the Highly Stereoselective Synthesis and Arylative Dimerization of Aspidosperma Alkaloids


  • We are grateful for financial support by NIH-NIGMS (GM074825). We thank Justin Kim, Owen Fenton, and Dr. Peter Müller for X-ray crystal structure analysis of 17⋅2 HCl.


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Building cycles: A strategy for the concise, stereoselective synthesis of aspidosperma alkaloids and related structures via a common putative diiminium ion intermediate is reported. The approach enables the dimerization of aspidosperma-type structures at the sterically hindered C2 position. The intermediate is prepared in one step from the shown lactam through an electrophilic double-cyclization cascade (see scheme; Tf=trifluoromethanesulfonyl).