Reactions of Cyclopropanone Acetals with Alkyl Azides: Carbonyl Addition versus Ring-Opening Pathways
作者:Scott Grecian、Pankaj Desai、Craig Mossman、Jennifer L. Poutsma、Jeffrey Aubé
DOI:10.1021/jo0711034
日期:2007.12.1
bond cleavage of the corresponding cyclopropanone, giving oxyallyl cations that were captured by azides. Aryl-substituted cyclopropanone acetals, when subjected to these conditions, afforded [1,2,3]oxaborazoles exclusively, which were also the result of C2−C3 bond rupture, azide capture, and then loss of nitrogen. In the reactions of n-hexyl-substituted cyclopropanone acetals with alkyl azides, a mixture
发现取代的环丙酮缩醛与烷基叠氮化物的路易斯酸介导的反应强烈依赖于酮组分的结构。当环丙酮缩醛用烷基叠氮化物处理时,分别获得了N-取代的 2-氮杂环丁酮和氨基甲酸乙酯产物,它们分别是由叠氮化物加成到羰基上,然后是扩环或重排产生的。BF 3 ·OEt 2存在下2,2-二甲基环丙酮缩醛与叠氮化物反应,获得的产物是 α-氨基-α'-重氮甲基酮,其产生于相应环丙酮的 C2-C3 键断裂,产生被叠氮化物捕获的氧烯丙基阳离子。芳基取代的环丙酮缩醛,在这些条件下,仅提供 [1,2,3] 恶唑啉,这也是 C2-C3 键断裂、叠氮化物捕获,然后失去氮的结果。在正己基取代的环丙酮缩醛与烷基叠氮化物的反应中,获得了 2-氮杂环丁酮和区域异构 [1,2,3] 恶硼唑的混合物。讨论了不同系统行为不同的原因。