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Paper | Regular issue | Vol 34, No. 2, 1992, pp.321-339
Published online, 1st January, 1970
DOI: 10.3987/COM-91-5922
Syntheses of (±)-Z-Geissoschizol, (±)-3-epi-Z-Geissoschizol, (±)-Corynantheidol, (±)-Dihydrocorynantheol, (±)-3-epi-Dihydrocorynantheol and the Corresponding Corynan-17-oic Acid Methyl Esters

Mauri Lounasmaa,* Reija Jokela, Birgit Tirkkonen, Jari Miettinen, and Minna Halonen

*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, SF-02150 Espoo, Finland

Abstract

The utility of the Claisen rearrangement using carefully separated, diastereoisomerric allylic alcohols (1a) and (1b) in the preparation of (±)-Z-geissoschizol (4a), (±)-3-epi-Z-geissoschizol (4b), (±)-corynantheidol (7a), (±)-dihydrocorynantheol (8a), (±)-3-epi-dihydrocorynantheol (8b) and the corresponding corynan-17-oic acid methyl esters (3a, 3b, 5a, 6a, and 6b) is shown. Special attention is paid to the stereochemical outcome of catalytic (PtO2) hydrogenation of the C(20) Z-ethylidene side chain.