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Unexpected catalysis: aprotic pyridinium ions as active and recyclable Brønsted acid catalysts in protic media

Barbara Procuranti and Stephen J. Connon*

*Centre for Synthesis and Chemical Biology, School of Chemistry, University of Dublin, Trinity College, Dublin 2, Ireland, Email:

B. Procuranti, S. J. Connon, Org. Lett., 2008, 10, 4935-4938.

DOI: 10.1021/ol802008m

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Simple pyridinium salt derivatives unexpectedly catalyze highly efficient acetalizations of aldehydes at ambient temperature. The aprotic catalyst promotes the formation of benzaldehyde dimethyl acetal at low loadings more efficiently than a protic Brønsted acid catalyst with a pKa of 2.2. The ionic catalyst can be readily recovered by precipitation and reused without loss of activity.

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Key Words

dimethyl acetals, organocatalysis

ID: J54-Y2008-3300