Synthesis 2009(23): 4082-4086  
DOI: 10.1055/s-0029-1217022
PSP
© Georg Thieme Verlag Stuttgart ˙ New York

Pyridinium Ion Catalysis of Carbonyl Protection Reactions

Barbara Procurantia, Lauren Mylesa, Nicholas Gathergoodb, Stephen J. Connon*a
a Centre for Synthesis and Chemical Biology, School of Chemistry, University of Dublin, Trinity College, Dublin 2, Ireland
Fax: +353(1)6712826; e-Mail: [email protected];
b School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
Further Information

Publication History

Received 9 July 2009
Publication Date:
22 October 2009 (online)

Abstract

Aprotic pyridinium ions incorporating electron-withdrawing substituents on the aromatic ring are powerful catalysts for the acetalization­ of aldehydes and the formation of dithianes, dithiolanes, dioxanes, and dioxolanes. Under optimum conditions the best catalyst can be used at a loading as low as 0.1 mol% and can outperform a Brønsted acid catalyst with a pK a of 2.2.

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