An attempt to construct the C/D ring system of parkacine by intramolecular cycloaddition of azomethine ylide and alkyne
作者:Wenxuan Zhang、Jiming Wang、Xihuan Luo、Xiangbao Meng、Zhongjun Li
DOI:10.1016/j.tetlet.2016.03.076
日期:2016.5
Intramolecular 1,3-dipolar cycloaddition of chiral hept-6-yne-azomethine ylide was attempted to construct the C/D ring system of a lycorine-type alkaloid parkacine (3). However, the cycloaddition reactions gave C/D ring-closure product with opposite configurations at 7- and 7a-carbons, comparing with the natural product. The unexpected epimerization of phenyl substituted chiral carbon may occur through
尝试手性庚6-炔-偶氮甲亚胺叶立德分子内的1,3-偶极环加成反应来构建赖氨酸类生物碱Parkacine的C / D环系统(3)。然而,与天然产物相比,环加成反应使C / D闭环产物在7-和7a-碳处具有相反的构型。分子内环加成之前,亚胺-烯胺互变异构可能会发生苯基取代的手性碳的意外的差向异构。