Synthesis of Demissidine Analogues from Tigogenin via Imine Intermediates
2021 ◽
Vol 22
(19)
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pp. 10879
A five-step transformation of a spiroketal side chain of tigogenin into an indolizidine system present in solanidane alkaloids such as demissidine and solanidine was elaborated. The key intermediate in the synthesis was spiroimine 3 readily obtained from tigogenin by its RuO4 oxidation to 5,6-dihydrokryptogenin followed by amination with aluminum amide generated in situ from DIBAlH and ammonium chloride. The mild reduction of spiroimine to a 26-hydroxy-dihydropyrrole derivative and subsequent mesylation resulted in the formation of 25-epidemissidinium salt or 23-sulfone depending on reaction conditions.
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2016 ◽
Vol 12
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pp. 2588-2601
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2019 ◽
Vol 41
(6)
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pp. 1039-1039
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2001 ◽
Vol 73
(7)
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pp. 1087-1101
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2018 ◽