Diasteroselective synthesis of oxazolidines and imidazolidines via the Lewis acid catalyzed C–C cleavage of aziridines
作者:Zheng Jiang、Jing Wang、Ping Lu、Yanguang Wang
DOI:10.1016/j.tet.2011.09.085
日期:2011.12
In this work, cis-2,5-disubstitutedoxazolidines were efficiently constructed via a regioselective C–C bond cleavage of N-tosylaziridine 2,2-dicaboxylates and a subsequent [3+2] cycloaddition with aromatic aldehydes in the presence of Zn(OTf)2. The reactions were highly diastereoselective to form oxazolidines in cis configurations. trans-2,5-Disubstituted imidazolidines were also diastereoselectively
在这项工作中,通过在N-甲苯磺酰氮丙啶2,2-二甲氧基化物上进行区域选择性的CC键断裂以及随后在Zn(OTf)存在下与芳族醛进行[3 + 2]环加成反应,可以有效地构建顺式-2,5-二取代的恶唑烷)2。反应高度非对映选择性,以顺式构型形成恶唑烷。反式还以亚胺为底物,AgOTf为催化剂,以类似方式非对映选择性地合成了-2,5-二取代的咪唑烷。基于对这两种反应的底物多样性的详细研究,包括氮丙啶,醛和亚胺对取代基的电子效应和空间效应,推测了非对映选择性形成顺式-2,5-的逐步机理二取代的恶唑烷和反式-2,5-二取代的咪唑啉。