unique tricyclic sesquiterpenoids, valeriananoids A–C 1–3, have been synthesized starting from bicyclo[2.2.2]octane-2,5-dione derivative 11, which was obtained by diastereoselective catalytic domino Michael reaction of oxophorone 5 with 8-phenylmenthyl acrylate 10 by LDA or silica-gel-base (NMAP-Li). The tricyclic ring was closed selectively by intramolecular 6-endo-trig mode cyclization of the ketyl radical
的独特
三环倍半萜天然的对映体,valeriananoids A-C 1 - 3,已经合成从
双环[2.2.2]辛烷-2,5-二酮衍
生物开始11,这是由非对映选择性催化多米诺迈克尔反应得到的oxophorone 5与8
LDA或
硅胶基质(N
MAP-Li)制成的
丙烯酸-苯基薄荷酯10。
三环通过酮基的分子内6-内-触发模式环化而选择性地封闭,所述酮基是由酮-
烯丙基醚25通过
萘或
萘二
甲酸钠生成的。