proceed as [4+2]-cycloadditions with inverse electron demand. In contrast, a polyfluorinated 2,4-cyclohexadienone with a methoxy group in the three-position shows no reaction with either α- or β-fluorostyrene, but does undergo rearrangement to give a polyfluorinated 2,5-cyclohexadienone. 4-Fluorooct-4-en-3-one is inert to all polyfluorinated 2,4-cyclohexadienones.
在碳3上带有一个额外的吸电子基团的多
氟2,4-环己二酮与α-和β-
氟代
苯乙烯的热反应产生非对映Diels–Alder产物的混合物。假定过程是协调一致的,这些反应将以[4 + 2]-环加成进行,且电子反需求。相反,在三位具有甲氧基的多
氟2,4-环己二酮与α-或β-
氟苯乙烯均不发生反应,但会发生重排而得到多
氟2,5-环己二酮。4-
氟八-4-烯-3-酮对所有多
氟2,4-环己二酮均呈惰性。