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Updated: May 22, 2026

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes
Published on: April 1, 2013
The Intramolecular Diels-Alder Reaction of Tryptamine-Derived Zincke Aldehydes Is a Stepwise Process
Hung V Pham1, David B C Martin, Christopher D Vanderwal
1Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569.
Abstract:
Computational studies show that the base-mediated intramolecular Diels-Alder of tryptamine-derived Zincke aldehydes, used as a key step in the synthesis of the Strychnos alkaloids norfluorocurarine and strychnine, proceeds via a stepwise pathway. The experimentally determined importance of a potassium counterion in the base is explained by its ability to preorganize the Zincke aldehyde diene in an s-cis conformation suitable to bicyclization. Computation also supports the thermodynamic importance of the generation of a stable enolate in the final reaction step. The thermal cycloreversion reaction of the Diels-Alder products is also found to proceed in a stepwise manner.
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