A novel phosphine-catalyzed [3 + 2] annulation of γ-substituted allenoates with succinimides was developed, which was successfully applied to the synthesis of 2-azaspiro[4.4]nonene-1,3-dione derivatives. The reaction afforded the desired products in moderate to high yields (up to 96%) with excellent regioselectivities and diastereoselectivities (up to >99:1 dr). A plausible reaction mechanism has also been proposed based on previous literature.

中文翻译：

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膦催化的[3 + 2]环化反应：2-氮杂螺[4.4]壬烯-1,3-二酮的高度区域选择性和非对映选择性合成

开发了一种新型的膦催化的琥珀酰亚胺与γ-取代的烯丙酸酯的[3 + 2]环化反应，将其成功地用于2-氮杂螺[4.4]壬烯-1,3-二酮衍生物的合成。反应，得到所需的产品在中到高的产率（高达96％）具有优异的区域选择性和非对映选择性（高达> 99 ：1个，DR）。基于先前的文献，也已经提出了合理的反应机理。