A Short Synthesis of <i>Ergot</i> Alkaloids and Evaluation of the 5-HT<sub>1/2</sub> Receptor Selectivity of Lysergols and Isolysergols
Nikhil R. Tasker, Peter Wipf
Abstract
Key transformations in a four-step synthesis of the ergot alkaloid scaffold include a novel cesium carbonate-mediated hydrogen autotransfer alkylation to generate the C(3)–C(4) bond and an intramolecular Heck reaction that directly establishes the C(9)–C(10) alkene of methyl lysergate. An ester reduction and a streamlined experimental procedure establish a readily scalable, expedient total synthesis of all four stereoisomers of lysergol and isolysergol, including the previously unknown (−)-lysergol, for pharmacological evaluation at 5-HT1A and 5HT2A,B,C receptors. A bicyclic scaffold is also characterized for the first time in the intramolecular Heck coupling.
Topics & Concepts
ChemistryIntramolecular forceHeck reactionAlkeneStereochemistryBicyclic moleculeAlkylationSelectivityAlkaloidCombinatorial chemistryHydrogen bondEne reactionMoleculeOrganic chemistryPalladiumCatalysisPlant and fungal interactionsChemical synthesis and alkaloidsAdvanced Synthetic Organic Chemistry