15 Jasmininの合成的研究

抄録

Jasminin is the bitter principle isolated from Jasminum primulium Hemsel. We have proposed the structure 1 for jasminin. Being interested in the unusual reactions and the structure of jasminin, we have continued the synthetic study. At first, the synthesis of the methyl ester hexaacetate 25, which was obtained by mild alkaline hydrolysis of jasminin, was considered. The key intermediate 7 was synthesized from (+)-carvone epoxide by Favorskii rearrangement. The acid 7 was then converted by a six-step reaction into the desired monool diacetates 19 and 20. Since the formal synthesis of the seco-iridoid moiety 4 was already repoted by Inouye, we obtained 4 from jasminin by mild alkaline hydrolysis. Treatment of the tosylate 30 with the sodium salt 31 in DMF afforded 25, which was identical with the authentic sample. Thus the structure of jasminin was established as in 1. The conversion of 25 into jasminin is now in progress.