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Upward Trend in Catalytic Efficiency of Rare‐Earth Triflate Catalysts in Friedel–Crafts Aromatic Sulfonylation Reactions

Upward Trend in Catalytic Efficiency of Rare‐Earth Triflate Catalysts in Friedel–Crafts Aromatic... A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The catalytic efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in catalytic efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water‐exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well‐known discontinuity in lanthanide properties. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Asian Journal of Organic Chemistry Wiley

Upward Trend in Catalytic Efficiency of Rare‐Earth Triflate Catalysts in Friedel–Crafts Aromatic Sulfonylation Reactions

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References (29)

Publisher
Wiley
Copyright
Copyright © 2014 Wiley Subscription Services, Inc., A Wiley Company
ISSN
2193-5807
eISSN
2193-5815
DOI
10.1002/ajoc.201402067
Publisher site
See Article on Publisher Site

Abstract

A series of 14 lanthanide (Ln) triflates were investigated as sustainable catalysts for aromatic sulfonylation reactions under microwave irradiation. The catalytic efficiency of the early triflates La(OTf)3–Eu(OTf)3 is good for long irradiation times. For the later lanthanides, yields reaching over 90 % were achieved for short irradiation periods. This was the case especially for Tm(OTf)3, Yb(OTf)3, and Lu(OTf)3, of which Yb(OTf)3 was the most efficient. The upward trend in catalytic efficiency therefore correlates with the lanthanide sequence in the periodic table. The results can be explained by the decrease in the radii of the Ln3+ ions, and the hydrolysis and water‐exchanges rate within the series. The results are in agreement with the first principal property value (t1) calculated by principal component analysis (PCA) published previously. A large drop in sulfonylation yield was obtained with Gd(OTf)3, which matched the “gadolinium break”; the well‐known discontinuity in lanthanide properties.

Journal

Asian Journal of Organic ChemistryWiley

Published: Sep 1, 2014

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