Probing the Mechanism of the Asymmetric Aminolysis of meso-Epoxides Catalyzed by a Proline-Based N,N′-Dioxide-Indium Tris(triflate) Complex
An exploration of the mechanism of the aminolysis of meso‐epoxides catalyzed by the proline‐based N,N′‐dioxide‐indium tris(triflate) complex was performed using control experiments, UV‐Vis spectroscopy, 1H NMR, electrospray ionization mass spectrometry (ESI‐MS) and scanning electron microscopy (SEM)...
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Published in | Advanced synthesis & catalysis Vol. 354; no. 8; pp. 1509 - 1518 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
WILEY-VCH Verlag
21.05.2012
WILEY‐VCH Verlag Wiley Wiley-VCH |
Subjects | |
Online Access | Get full text |
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Summary: | An exploration of the mechanism of the aminolysis of meso‐epoxides catalyzed by the proline‐based N,N′‐dioxide‐indium tris(triflate) complex was performed using control experiments, UV‐Vis spectroscopy, 1H NMR, electrospray ionization mass spectrometry (ESI‐MS) and scanning electron microscopy (SEM). Control experiments disclosed that the ligand‐to‐indium tris(triflate) ratio, the catalyst loading, the concentration, and the presence of 4 Å MS have dramatic effects on this reaction with regard to both the yield and the enantioselectivity. Combined with control experiments, UV‐Vis spectroscopy, 1H NMR, ESI‐MS and SEM analyses revealed that molecular sieves perform multiple functions in the catalysis. A plausible molecular sieves‐assisted reaction pathway was proposed. In this pathway, molecular sieves perform (i) as desiccant to in situ dry the reaction system, (ii) as proton transfer agent to accelerate the catalysis, and (iii) as counter ion source to preserve the electroneutrality of the transition states. Besides, the generality of the substrate scope was further explored; excellent yields (up to 99%) and enantioselectivities (up to 99% ee) were obtained. |
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Bibliography: | istex:E787CEAFFA56D5E33173E572D02E15D36A25F24C ark:/67375/WNG-GSJ9SR22-D Youth Foundation of Sichuan University - No. 2008009 National Natural Science Foundation of China - No. 20902064 ArticleID:ADSC201200142 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1615-4150 1615-4169 |
DOI: | 10.1002/adsc.201200142 |