A practical synthesis of Entecavir (1) has been accomplished in 10 steps with 21% overall yield. The key steps to construct the five-membered carbocyclic framework 2 are a ring-closing metathesis and a diethyl-aluminum 2,2,6,6-tetramethyl piperidide (DA-TMS) mediated epoxide isomerization. Furthermore, the guanine was introduced by modified Mitsunobu reaction. (C) 2012 Elsevier Ltd. All rights reserved.
Total Synthesis of Entecavir: A Robust Route for Pilot Production
作者:Hua Xu、Fang Wang、Weicai Xue、Yunjie Zheng、Qi Wang、Fayang G. Qiu、Yehua Jin
DOI:10.1021/acs.oprd.8b00007
日期:2018.3.16
A practicalsyntheticroute for pilot production of entecavir is described. It is safe, robust, and scalable to kilogram scale. Starting from (S)-(+)-carvone, this syntheticroute consists of a series of highly efficient reactions including a Favorskii rearrangement-elimination-epimerization sequence to establish the cyclopentene skeleton, the Baeyer–Villiger oxidation/rearrangement to afford the correct