Highly Stereoselective Assembly of α-Carbolinone Skeletons via N-Heterocyclic Carbene-Catalyzed [4 + 2] Annulations
作者:Kai-Chuan Yang、Qing-Zhu Li、Yu Liu、Qing-Qing He、Yue Liu、Hai-Jun Leng、Ai-Qiong Jia、Shanmugavel Ramachandran、Jun-Long Li
DOI:10.1021/acs.orglett.8b03277
日期:2018.12.7
A series of iminoindoline-derived alkenes was found to be a new class of excellent aza-diene electrophiles in NHC-catalyzed asymmetric [4 + 2] cyclizations. This transformation is mainly characterized by excellent compatibility, which allows aza-diene substrates to incorporate various substituents and functionalities, including (hetero)aryl, (linear or branched)alkyl, alkenyl, alkynyl, and ester groups
在NHC催化的不对称[4 + 2]环化反应中,发现了一系列亚氨基二氢吲哚衍生的烯烃是一类新的优异的氮杂二烯亲电试剂。该转变的主要特征是优异的相容性,该相容性使氮杂二烯底物能够结合各种取代基和官能团,包括(杂)芳基,(直链或支链)烷基,烯基,炔基和酯基。使用该方法轻松合成了40个所需的四氢-α-咔啉酮实例,收率高达99%,ee大于99%。