Formal double (3+2)-cycloaddition of in situ generated tri­fluoroacetonitrile imines with alkoxyallenes proceeds in a highly regio- and diastereoselective manner to afford anti-configured spirobipyrazolines as the exclusive 2:1 adducts. Initial stepwise addition of the title electron-deficient 1,3-dipoles onto cumulenic reaction partner is pos­tulated to explain the observed reaction pathway.

中文翻译：

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通过氟化腈亚胺与烷氧基丙二烯的双 (3+2)-环加成直接获得三氟甲基化螺双吡唑啉

原位生成的三氟乙腈亚胺与烷氧基丙二烯的正式双 (3+2) 环加成反应以高度区域选择性和非对映选择性的方式进行，以提供反构型的螺二吡唑啉作为独有的 2:1 加合物。假设将标题缺电子 1,3-偶极子初始逐步添加到累积反应伙伴上以解释观察到的反应途径。