The selectivity between [2 + 2] and [2 + 4] cycloadditions of cyclopentyne with spiro[2.4]nona-2,4-diene depends on the mode of generating the cycloalkyne. Using diazomethylenecyclobutane and (bromocyclobutylidenemethyl)trimethylsilane as precursors affords cyclopentyne in an unencumbered form, whereas using dibromomethylenecyclobutane and 1,2-dibromocyclopentene yields a cyclopentyne-lithium bromide
环戊炔与螺[2.4] nona-2,4-二烯的[2 + 2]和[2 + 4]环加成反应之间的选择性取决于生成环炔的方式。使用重氮
亚甲基环丁烷和(
溴代
环丁烯基甲基)三甲基
硅烷作为前驱体可以不受阻碍的形式提供环戊炔,而使用二
溴亚甲基环丁烷和
1,2-二溴环戊烯可以生成环戊炔-
溴化锂络合物。