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Updated: May 8, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Concise synthesis of the multiply oxygenated ABC-ring system of the dihydro-β-agarofurans
Tomochika Ishiyama1, Daisuke Urabe, Hiroki Fujisawa
1Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
Abstract:
The multiply oxygenated ABC-ring system of the dihydro-β-agarofurans was synthesized by employing two highly stereoselective reactions. The quinidine-catalyzed Diels-Alder reaction between a chiral dienophile and 3-hydroxy-4-methyl-2-pyrone simultaneously installed the C2-stereogenic center and two contiguous tetrasubstituted carbon centers (C5 and C10) of the A-ring. After 12 additional transformations, the aldol reaction of the resulting spiral AC-ring cyclized the B-ring with stereoselective introduction of the C7- and C8-centers.
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