Michael reactions of 2,5-dioxocyclohexane-1,4-dicarboxylates with methyl vinyl ketone yield bis-adducts that can be further cyclized in a Robinson-type annulation to give s-indacene derivatives as single diastereomers. The carboxylate functions of this scaffold can be deprotected and subsequently decarboxylated to yield tricyclic products with a central aromatic ring.
迈克尔反应中,2,5-二氧杂
环己烷-1,4-二
羧酸酯与甲基
乙烯基酮反应生成双加成物,这些加成物可以进一步通过罗宾逊式烯烃环化反应形成s-
茴香烯衍
生物,且以单一的绝对异构体存在。该骨架的
羧酸盐功能可以去保护,随后进行脱羧,生成具有中央芳环的
三环产物。