4-Hydroxycoumarin ( and ) as well as 2-hydroxy-2,5-cyclohexadien-1-ones – were reacted with KO2/18-crown-6 in benzene. Initial deprotonation of the enol hydrogen was followed by nucleophilic attack by O2/t- (for and ) and/or autoxidation of the resulting anion (for and –). A convenient synthesis of 2,3-unsaturated-δ-valerolactones from the corresponding 2-cyclohexen-1-ones is also described.
3-和
4-羟基
香豆素(和)以及2-羟基-2,5-环
己二烯-1-酮-用KO反应2 /
18-冠-6苯。烯醇氢的初始去质子化之后是O 2 / t-(对于和)的亲核攻击和/或所得阴离子的自氧化(对于和- )。还描述了由相应的
2-环己烯-1-酮方便地合成2,3-不饱和-
δ-戊内酯。