We report here a convenient method to construct polysubstituted azetidines and 2,4-dioxo-1,3-diazabicyclo[3.2.0] compounds with high stereoselectivities in a one-pot reaction mediated by I₂. The tetramethylguanidine (TMG)/I₂-mediated formal [2 + 2] cycloaddition reaction of α-amidomalonate 1 with enones 2 affords functionalized azetidine derivatives 4 in moderate to good yields with high diastereoselectivity. When the α-ureidomalonate 5 is used instead of 1, 2,4-dioxo-1,3-diazabicyclo[3.2.0]heptanes 8 and 2,4-dioxo-1,3-diazabicyclo[3.2.0]heptenes 9 can be prepared selectively through the control of solvent and temperature. 2,4-Dioxo-1,3-diazabicyclo[3.2.0]heptanes 8 can further undergo ring-opening reactions with different nucleophilic reagents to afford the corresponding polyfunctionalized azetidine derivatives 13–16 with high steroselectivities.

中文翻译：

---

I ₂介导的高立体选择性一锅合成氮杂环丁烷和2,4-二氧代-1,3-二氮杂双环[3.2.0]化合物

我们在这里报告一种方便的方法来构建由I ₂介导的一锅反应中具有高立体选择性的多取代的氮杂环丁烷和2,4-二氧代-1,3-二氮杂双环[3.2.0]化合物。α-氨基天冬氨酸盐1与烯酮2的四甲基胍（TMG）/ I ₂介导的正式[2 + 2]环加成反应以中等至良好的收率提供了高非对映选择性的官能化氮杂环丁烷衍生物4。当α-ureidomalonate 5代替1，2,4-二氧代-1,3-二氮杂双环[3.2.0]庚烷8和2,4-二氧代-1,3-二氮杂双环[3.2.0]庚烯9通过控制溶剂和温度可以选择性地制备。2,4-二氧代-1,3-二氮杂双环[3.2.0]庚烷8可以进一步经历与不同的亲核试剂，以得到相应的多官能化的氮杂环丁烷衍生物的开环反应13 - 16具有高steroselectivities。