ORGN 108 |
Rare-earth metal-catalyzed sulfonylation reactions of N-(phenylsulfonyl)pyrroles
| Daniel M. Ketcha and David J. Malwitz. Department of Chemistry, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435 |
In contrast to the expected “normal” C-2 substitution of pyrroles, it has recently been disclosed by Mizuno that the sulfonation of pyrrole using sulfur trioxide-pyridine complex afforded 3-sulfonated derivatives. Similarly, we have initiated studies of the regioselectivity of sulfonylation reactions upon N-(phenylsulfonyl)pyrrole. Since rare-earth catalysts have shown promise in both Friedel-Crafts acylation and sulfonylation reactions of aromatics, we chose to explore the use of such catalysts (e.g., Sc(OTf)3, Yb(OTf)3, Bi(OTf)3, In(OTf)3 and InCl3 for this purpose using a variety of solvents and temperatures. To this end N-(phenylsulfonyl)pyrrole, and some α-substituted N-(phenylsulfonyl)pyrroles were treated with a variety of sulfonyl- as well as sulfamoyl chlorides in the presence of these catalysts. We find that sulfonylation occurs exclusively at the C-3 position at the elevated temperatures required to effect reaction. The scope and limitations of these reactions will be discussed as will the role of possible rearrangement processes under these conditions. |
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New Reactions and Methodology, Metal-Mediated Reactions, Heterocycles and Aromatics
8:00 PM-10:00 PM, Sunday, March 28, 2004 Anaheim Convention Center -- Hall A, Poster
Division of Organic Chemistry
The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004
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