3-(7-Methyl-1,4-dioxaspiro[4.5]decan-7-yl)propanal 、
ethyl 6-methyl-2-(trimethylsilyl)hept-5-enoate 在
lithium diisopropyl amide 作用下,
生成 ethyl (+/-)-6-methyl-2-<(Z)-3-(7-methyl-1,4-dioxaspiro<4,5>dec-7-yl)propylidene>-5-heptenoate 、 ethyl (+/-)-6-methyl-2-<(E)-3-(7-methyl-1,4-dioxaspiro<4,5>dec-7-yl)propylidene>-5-heptenoate