A new and effective approach toward epoxide opening of a 7,17-seco–7,8-epoxy-C19-diterpenoid alkaloid is herein described. The starting epoxide was prepared from naturally occurring yunnaconitine via a nine-step transformation. Treatment of this epoxide with trifluoroacetic anhydride in dioxane at 110oC followed by reduction with sodium boron hydride generated two epoxide opening compounds 7 and 8. Each of their structures is characteristic of a Δ8,15 bridgehead double bond and a 7β-oxygen-substituted group.
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6.
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8.
ChengH, XuL, ChenDL, ChenQH, WangFP. (2012) Construction of functionalized B/C/D-ring system of C19-diterpenoid alkaloids via intramolecular Diels-Alder reaction followed by Wagner-Meerwein rearrangement. Tetrahedron, 68, 1171–1176.
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LiangXX, TangP, ChenQH, WangFP. (2012) Synthesis of taxane ABC tricyclic skeleton from lycoctonine. Natural Product Communications, 7, 697–703.
10.
LiuZG, XuL, ChenQH, WangFP. (2012) Construction of A/E/F ring systems of C19-diterpenoid alkaloids with both C-1 and C-6 oxygen functions. Tetrahedron, 68, 159–165.
11.
JiH, ChenQH, WangFP. (2009) A novel conversion of C19-diterpenoid alkaloids into aconane-type diterpenes with eight-membered ring system via skeletal rearrangement of corresponding diazonium derivatives. Chemical and Pharmaceutical Bulletin, 57, 233–239.
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13.
WangL, ChenQH, WangFP. (2012) Unusual reactions of a 7,17-seco-type C19-diterpenoid alkaloid derived from deltaline. Natural Product Communications, 7, 721–724.
14.
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