Broadening the Scope of the Zwitterionic 1,3-Diaza-Claisen Rearrangement through a Tethering Strategy
作者:Matthew W. Luedtke、Joseph Pisano、Lucas Paquin、Joel Walker、José S. Madalengoitia
DOI:10.1021/acs.joc.1c00667
日期:2021.6.18
Expansion of the scope of the 1,3-diaza-Claisen rearrangement beyond bridged-bicyclic tertiary allylic amines has been investigated through a tethering strategy. Isothioureas tethered to tertiary allylic amines are converted to carbodiimides through a reaction with AgOTf/Et3N. Intramolecular cyclization of the tertiary allylic amine to the carbodiimide equilibrates with a zwitterionic intermediate
已经通过束缚策略研究了 1,3-二氮杂-克莱森重排的范围超出桥连双环叔烯丙胺的范围。与叔烯丙基胺相连的异硫脲通过与 AgOTf/Et 3反应转化为碳二亚胺N. 叔烯丙基胺分子内环化成碳二亚胺与两性离子中间体平衡。加热碳二亚胺/两性离子得到重排产物。加热带有氘代烯丙基的碳二亚胺/两性离子会导致氘标记的混乱,这与涉及异裂烯丙基 C-N 键的离子机制一致,然后在任一末端碳捕获烯丙基阳离子。离子机制归因于银盐污染,因为在加热之前通过硅胶推动氘标记的碳二亚胺/两性离子会导致干净的氘转位与 sigmatropic 机制一致,并且添加回银盐会导致氘混乱。全面的,束缚策略将重排的范围扩大到更简单的烯丙基底物。σ 重排的密度泛函理论 (DFT) 计算与在无银条件下运行的反应观察到的反应性趋势一致。