Asymmetric Synthesis of Pyrrolo[2,1-a]isoquinoline Derivatives by 1,3-Dipolar Cycloadditions of Stabilized IsoquinoliniumN-Ylides with Sulfinyl Dipolarophiles
摘要:
Enantiomerically pure pyrrolo[2,1-a]isoquinoline derivatives are obtained by 1,3-dipolar reactions of isoquinolinium azomethine ylides with enantiopure 3-p-tolylsulfinylacrylonitriles, tert-butyl (2E)-4,4-diethoxy-2-p-tolylsulfinylbut-2-enoate, and 5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones. Reactions evolve through the anti conformation of the ylide with complete regioselectivity. The facial selectivity is completely controlled by the configuration of the sulfinyl sulfur for acyclic dipolarophiles, whereas it is high (dr 83/17 or 89/11) but controlled by the C-5 configuration for sulfinylfuranones. Complete endo selectivity is observed with cyclic dipolarophiles and substituted acrylonitriles, but it is low with butenoate. The sulfinyl group also exerts a positive influence on the dipolarophilic reactivity toward these ylides.
In Situ Generation of Quinolinium Ylides from Diazo Compounds: Copper-Catalyzed Synthesis of Indolizine
作者:Rongxiang Chen、Yanwei Zhao、Hongmei Sun、Ying Shao、Yudong Xu、Meihua Ma、Liang Ma、Xiaobing Wan
DOI:10.1021/acs.joc.7b01042
日期:2017.9.15
The Cu-catalyzedthree-component reaction between quinolines, diazo compounds, and alkenes has been established for direct construction of indolizine derivatives via quinolinium ylides. This methodology is distinguished by the use of a commercially inexpensive catalyst and readily available starting materials, wide substrate scope, and operational simplicity.