An attempted approach to the tricyclic core of haliclonin A：Structural elucidation of the final product by 2D NMR  

作　　者：Yan-Jiao Gao Shi-Peng Luo Jian-Liang Ye Pei-Qiang Huang 

机构地区：[1]Department of Chemistry, Fujian Provincial Key Laboratory of Chemical Biology, iChEM (Collaborative lnnovaCion Center of Chemistry for Energy Materials),College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China

出　　处：《Chinese Chemical Letters》2017年第6期1176-1181,共6页中国化学快报（英文版）

基　　金：the National Natural Science Foundation of China(No.21472153);the National Basic Research Program(973 Program)of China(No.2010CB833200);the SKL of Xiamen University(No.201509);the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education,China,for financial support

摘　　要：We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alkenyl isocyanide to build the bridged ring system,and ring-closing metathesis（RCM） reaction to form the macrocycle.Execution of the synthetic plan ultimately resulted in a diazatricyclic compound.By means of 2D NMR techniques,the structure of this compound was revealed to an unexpected product 8.Analysis of the synthetic pathways allowed concluding that the unexpected product is a result of an ＂unexpected＂ migration of olefinic bond during dioxolanation of the 2-cyclohexenone derivative 7.This investigation also resulted in a concise construction of the functionalized hexahydro-1H-isoindole-1,5（4H）-dione 12 and the macrocyclic tricyclic ring system 8.We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alkenyl isocyanide to build the bridged ring system,and ring-closing metathesis（RCM） reaction to form the macrocycle.Execution of the synthetic plan ultimately resulted in a diazatricyclic compound.By means of 2D NMR techniques,the structure of this compound was revealed to an unexpected product 8.Analysis of the synthetic pathways allowed concluding that the unexpected product is a result of an ＂unexpected＂ migration of olefinic bond during dioxolanation of the 2-cyclohexenone derivative 7.This investigation also resulted in a concise construction of the functionalized hexahydro-1H-isoindole-1,5（4H）-dione 12 and the macrocyclic tricyclic ring system 8.

关 键 词：2D NMR Ring closing metathesis Macrocycles Lactams Structure revision Cyclization 

分 类 号：O621.3[理学—有机化学]