ORGN 146 |
| N-(Phenylsulfonyl)pyrrole displays a tunable reactivity in Friedel-Crafts acylation reactions, wherein the site of substitution is controlled by the nature of the acid catalyst employed. Whereas the room temperature reaction of this substrate with “environmentally friendly” catalysts such as montmorillonite or rare earth triflates affords predominantly C-2 substitution, the use of rare earth triflates in the presence of the additive lithium perchlorate in nitromethane effects acyl group rearrangements to the C-3 isomer. A reexamination of these processes under both thermal and microwave conditions indicates that the aforementioned conditions as well as lithium perchlorate alone, and/or catalytic amounts of triflic acid produce a mixture of the C-2 and C-3 isomers along with varying amounts of diacylated adducts. Additionally, such rearrangement processes are observed in the Friedel-Crafts acylation of alkyl-substituted 1-(phenylsulfonyl)pyrroles under these conditions.
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Heterocycles, Aromatics, Materials, Devices, Switches, Combinatorial Chemistry, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, 13 March 2005 Convention Center -- Hall D, Poster
Division of Organic Chemistry |
