Catalytic Asymmetric Spirocyclizing Diels–Alder Reactions of Enones: Stereoselective Total and Formal Syntheses of α-Chamigrene, β-Chamigrene, Laurencenone C, Colletoic Acid, and Omphalic Acid
Santanu Ghosh, Johannes Eike Erchinger, Rajat Maji, Benjamin List
Abstract
-enones with dienes to give spirocyclanes. The obtained products feature highly congested quaternary stereogenic spirocenters and are used in concise total and formal syntheses of several sesquiterpenes, including of α-chamigrene, β-chamigrene, laurencenone C, colletoic acid, and omphalic acid. The stereo- and regioselectivities of our spirocyclizing cycloaddition are effectively controlled by strongly acidic and confined imidodiphosphorimidate catalysts. Computational studies shed light on the origin of reactivity and selectivity.
Topics & Concepts
ChemistryStereoselectivityCatalysisDiels–Alder reactionOrganic chemistryStereochemistryChemical synthesis and alkaloidsAsymmetric Synthesis and CatalysisMicrobial Natural Products and Biosynthesis