دورية أكاديمية
Direct, enantioselective synthesis of pyrroloindolines and indolines from simple indole derivatives
| العنوان: | Direct, enantioselective synthesis of pyrroloindolines and indolines from simple indole derivatives |
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| المؤلفون: | Wang, Jane Ni Haoxuan, Reisman, Sarah E. |
| المصدر: | Tetrahedron, 69(27-28), 5622-5633, (2013-07-08) |
| بيانات النشر: | Elsevier |
| سنة النشر: | 2013 |
| المجموعة: | Caltech Authors (California Institute of Technology) |
| مصطلحات موضوعية: | Pyrroloindoline, (3+2) cycloaddition, Enantioselective catalysis |
| الوصف: | The (R)-BINOL·SnCl_4-catalyzed formal (3+2) cycloaddition between 3-substituted indoles and benzyl 2-trifluoroacetamidoacrylate is a direct, enantioselective method to prepare pyrroloindolines from simple starting materials. However, under the originally disclosed conditions, the pyrroloindolines are formed as mixtures of diastereomers, typically in the range of 3:1 to 5:1 favoring the exo-product. The poor diastereoselectivity detracts from the synthetic utility of the reaction. We report here that use of methyl 2-trifluoroacetamidoacrylate in conjunction with (R)-3,3′-dichloro-BINOL·SnCl_4 provides the corresponding pyrroloindolines with improved diastereoselectivity (typically ≥10:1). Guided by mechanistic studies, a one-flask synthesis of enantioenriched indolines by in situ reduction of a persistent iminium ion is also described. ; © 2013 Elsevier Ltd. Received 18 January 2013. Received in revised form 28 March 2013. Accepted 1 April 2013. Available online 6 April 2013. We thank Dr. David VanderVelde for assistance with NMR structure determination, as well as Prof. Brian Stoltz, Dr. Scott Virgil, and the Caltech Center for Catalysis and Chemical Synthesis for access to analytical equipment. We also thank Sigma-Aldrich for a kind donation of chemicals. NMR spectra were obtained on a spectrometer funded by the NIH (RR027690). Fellowship support was provided by Natural Sciences and Engineering Research Council (NSERC) of Canada (J.N., PGS D scholarship). S.E.R. is a fellow of the Alfred P. Sloan Foundation and a Camille Dreyfus Teacher-Scholar. Financial support from the California Institute of Technology, the NIH (NIGMS RGM097582A), and the donors of the ACS Petroleum Research Fund is gratefully acknowledged. ; Accepted Version - nihms-474474.pdf |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | unknown |
| العلاقة: | https://doi.org/10.1016/j.tet.2013.04.003Test; oai:authors.library.caltech.edu:277fm-k6q92; https://www.ncbi.nlm.nih.gov/pmc/PMC3769991Test; eprintid:39742; resolverid:CaltechAUTHORS:20130802-142338946 |
| DOI: | 10.1016/j.tet.2013.04.003 |
| الإتاحة: | https://doi.org/10.1016/j.tet.2013.04.003Test https://www.ncbi.nlm.nih.gov/pmc/PMC3769991Test |
| حقوق: | info:eu-repo/semantics/openAccess ; Other |
| رقم الانضمام: | edsbas.96513D94 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1016/j.tet.2013.04.003 |
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