Direct and Stereoselective Synthesis of Diversely Substituted 2,4-<i>trans</i>-(NH)-Pyrrolidines by Copper(I)-Catalyzed Radical Cyclization at Low Temperature
作者:Ram N. Ram、Dharmendra Kumar Gupta
DOI:10.1002/adsc.201600844
日期:2016.10.20
applications of the products in the preparation of useful 4‐chloro‐NH‐pyrrole in a single step, has also been demonstrated. A quick, mild and general method involving simple addition of trichloroacetic acid/dimethyl sulfoxide (CCl3CO2H‐DMSO) solution to readily accessible N‐allylaldimines and ketimines tolerating acid‐sensitive and highly deactivating substituents was developed to access the amine precursors.
这项工作描述了带有未保护的NH-基团的β-卤代乙基烯丙基胺在铜(I)催化下的自由基环化成功,同时保持了催化剂的氧化还原活性。环化在0°C时发生区域和非对映选择性,并直接以高分离产率提供不同取代的1,3-反式-(NH)-吡咯烷。提出了庞大的铜络合物参与环化步骤,这可能是非对映选择性的可能原因。还证明了该产品在一步制备有用的4-氯-NH-吡咯中的合成应用。一种快速,温和且通用的方法,包括将三氯乙酸/二甲亚砜(CCl 3 CO 2 H-DMSO)溶液简单地添加到易于获取的N中开发了可耐受酸敏感性和高度失活的取代基的烯丙醛和酮亚胺,以获取胺前体。