Take two: By employing two equivalents of an aldehyde in an asymmetricorganocatalyticdominoreaction, the nucleophilic enamine intermediate is also converted into the corresponding iminium species through oxidation with o‐iodoxybenzoic acid. Thus, polyfunctionalized cyclohexene derivatives are formed from two simple starting materials in good yields and stereoselectivities (see scheme; Bn=benzyl
A One‐Pot Ring‐Opening/Ring‐Closure Sequence for the Synthesis of Polycyclic Spirooxindoles
作者:Ji‐Wei Ren、Qing‐Lan Zhao、Jun‐An Xiao、Peng‐Ju Xia、Hao‐Yue Xiang、Xiao‐Qing Chen、Hua Yang
DOI:10.1002/chem.201900409
日期:2019.3.27
One‐pot ring‐opening/ring‐closure process of combining methyleneindolinone with 3‐aminooxindole has been developed in this work. Novel polycyclic spirooxindoles were efficiently assembled under mild conditions in high yields (up to 95 %) with moderate to good diastereoselectivities (up to >95:5 d.r.) through simple filtration.
Regioselective ring expansion followed by H-shift of 3-ylidene oxindoles: a convenient synthesis of N-substituted/un-substituted pyrrolo[2,3-<i>c</i>] quinolines and marinoquinolines
and metal-free protocol for the synthesis of 4-oxo-4,5-dihydro-3H-pyrrolo[2,3-c]quinolines. The present method under mild reaction conditions with wide functional group compatibility gives several unexplored N-substituted/unsubstituted 4-oxo-4,5-dihydro-3H-pyrrolo[2,3-c]quinolines and marinoquinolines in good to excellent yields. Mechanistic insights for the synthesis of N-substituted pyrroloquinolines
在此,我们报告了一种用于合成 4-oxo-4,5-dihydro-3 H -pyrrolo[2,3 - c ] 喹啉的简单且无金属的方案。本方法在温和的反应条件下具有广泛的官能团相容性,以良好至优异的产率提供了几种未开发的 N-取代/未取代 4-oxo-4,5-dihydro-3 H -pyrrolo [2,3 - c ] 喹啉和 marinoquinolines。N-取代吡咯并喹啉合成的机理研究揭示了 3-亚基氧吲哚的扩环和 H 位移是关键步骤。
Catalytic Asymmetric Synthesis of Cyclopentene-spirooxindoles Bearing Vinylsilanes Capable of Further Transformations
作者:Angel A. Cobo、Brittany M. Armstrong、James C. Fettinger、Annaliese K. Franz
DOI:10.1021/acs.orglett.9b02852
日期:2019.10.18
for the enantioselective formation of cyclopentene-spirooxindoles containing vinylsilanes. Using a Sc(OTf)2/PyBOX/BArF complex, the spiroannulation of allenylsilanes affords products with >94:6 dr and >90:10 er. The effect of the counterion and ligand to control selectivity is discussed. The transformation of the vinylsilane is demonstrated using cross-coupling, epoxidation, and Tamao–Fleming oxidation
Metal-free visible-light-promoted intermolecular [2+2]-cycloaddition of 3-ylideneoxindoles
作者:Ling-Ling Wu、Gao H. Yang、Zhi Guan、Yan-Hong He
DOI:10.1016/j.tet.2017.02.035
日期:2017.4
The Rose Bengal sensitized intermolecular [2 + 2]-cycloaddition of 3-ylideneoxindoles for the synthesis of spirocyclic oxindoles was developed successfully under visible light irradiation conditions. The cycloaddition products were obtained in good yields (up to 93%) with excellent diastereoselectivity and regioselectivity by using a low loading of Rose Bengal (0.125 mol%) as a triplet sensitizer.