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Synthesis 2009(23): 4082-4086
DOI: 10.1055/s-0029-1217022
DOI: 10.1055/s-0029-1217022
PSP
© Georg Thieme Verlag
Stuttgart ˙ New York
Pyridinium Ion Catalysis of Carbonyl Protection Reactions
Further Information
Received
9 July 2009
Publication Date:
22 October 2009 (online)
Publication History
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.
Key words
organocatalysis - catalysis - aldehydes - acetals - dithianes
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