An unprecedented gedunin rearrangement reaction converts a methyl group into the methylene group of a cyclopropyl ring

• Published in: Tetrahedron Vol. 70; no. 37; pp. 6656 - 6662
• Main Authors: Okhale, Samuel E., Decatur, John, Itagaki, Yasuhiro, Amupitan, Joseph O., Ndukwe, George I., Ellestad, George, Okogun, Joseph I.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 16-09-2014
• Subjects: Acid-catalysed rearrangement reaction; Chemosystematics; Conversion; Cyclopropane; Derivatives; Formations; Gedunin; Intramolecular cyclopropanation; Methylene; Organic compounds; Phylogenetic history; Rings (mathematics); Tetrahedrons; UNCTWVYPAGCYCT-PCBHMJPESA-N; FMCDBTGUTFESRD-SFUWRAHYSA-R; WXLSHHWRMCYHMP-XBEJNUCZSA-N; SLOJJRNNAFSENY-XUCUVXBGSA-N; Acid-catalysed rearrangement reaction; Phylogenetic history; Chemosystematics; STKFOALZWQROCZ-UHFFFAOYSA-N; NHULPMLHRXYZPS-UYBGAYNYSA-N; Intramolecular cyclopropanation; Gedunin; MRXSSPHGGIRXCZ-SKEZZINASA-N
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2014.06.067

Herein we describe an unprecedented formation of a cyclopropane ring through the conversion of a methyl group that was not functionalized for the purpose. In a one-step reaction, 7-deacetoxy-7α-hydroxygedunin (4) afforded two new gedunin derivatives, namely 7-deacetoxy-13,14,18-cyclopropyl-7α,15β, 17ξ-trihydroxy-gedu-16-oic acid (7) and 7-deacetoxy-9,11-en-7α,15β-dihydroxygedunin (8) along with the known 7-deacetoxy-7,9-diene-15β-hydroxygedunin (5).
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