Total synthesis of epoxyquinols A, B, and C and epoxytwinol A and the reactivity of a 2H-pyran derivative as the diene component in the Diels-Alder reaction

Mitsuru Shoji, Hiroki Imai, Makoto Mukaida, Ken Sakai, Hideaki Kakeya, Hiroyuki Osada, Yujiro Hayashi

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(Chemical Equation Presented). Full details of two versions of the total synthesis of epoxyquinols A, B, and C and epoxytwinol A (RKB-3564D) are described. In the first-generation synthesis, the HfCL4-mediated diastereoselective Diels-Alder reaction of furan with Corey's chiral auxiliary has been developed. In the second-generation synthesis, a chromatography-free preparation of an iodolactone, by using acryloyl chloride as the dienophile in the Diels-Alder reaction of furan, and the lipase-mediated kinetic resolution of a cyclohexenol derivative have been developed. This second-generation synthesis is suitable for large-scale preparation. A biomimetic cascade reaction involving oxidation, 6π-electrocyclization, and then Diels-Alder dimerization is the key reaction in the formation of the complex heptacyclic structure of epoxyquinols A, B, and C. Epoxytwinol A is synthesized by the cascade reaction composed of oxidation, 6π-electrocyclization, and formal [4 + 4] cycloaddition reactions. A 2H-pyran, generated by oxidation/6π- electrocyclization, acts as a good diene, reacting with several dienophiles to afford polycyclic compounds in one step. An azapentacyclic compound is synthesized by a similar cascade reaction composed of the four successive steps: oxidation, imine formation, 6π-azaelectrocyclization, and Diels-Alder dimerization.

Original languageEnglish
Pages (from-to)79-91
Number of pages13
JournalJournal of Organic Chemistry
Issue number1
Publication statusPublished - 2005 Jan 7


ASJC Scopus subject areas

  • Organic Chemistry

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