Enantioselective Spirocyclizations from Tryptophanol-Derived Oxazolopiperidone Lactams
摘要:
A straightforward synthetic route to enantiopure spiro[indole-3,3'-indolizidines] is reported. The key step is a Lewis acid promoted cyclization of a N-a-tosyltryptophanol-derived oxazolopiperidone lactam in the presence of Et3SiH.
已开发出对苯并[ a ]-和吲哚并[2,3- a ]喹啉联苯胺的对映选择性两步法。它由(i)外消旋或前手性δ-氧代(二)酯与(S)-(3,4-二甲氧基苯基)丙氨醇或(S)-色氨酸的立体选择性环缩合反应涉及动态动力学拆分和/或对映体或非对映体酯基的区分,和(ii)随后利用所得恶唑并哌啶酮内酰胺中存在的被掩蔽的N-酰基亚氨基亚胺离子在芳环上进行立体控制环化。
Enantioselective Synthesis of Spiro[indolizidine-1,3′-oxindoles]
作者:Maria Pérez、Carlos Ramos、Lucia Massi、Silvia Gazzola、Chiara Taglienti、Nihan Yayik、Elies Molins、Antonio Viayna、F. Javier Luque、Joan Bosch、Mercedes Amat
DOI:10.1021/acs.orglett.7b01818
日期:2017.8.4
A three-step procedure for the enantioselective synthesis of spiro[indolizidine-1,3′-oxindoles], consisting of a stereoselective cyclocondensation reaction between (S)-tryptophanol and a prochiral or racemic δ-oxoester, bromination of the resulting oxazolopiperidone lactam, and a final stereoselective spirocyclization, is reported.