A Mild PPTS-Catalyzed Acetalization of α,β-Unsaturated Aldehydes: The First Single-Step Protocol towards Benzylic Acetals

Abstract

A mild and convenient procedure for the synthesis of highly sensitive benzylic acetals from α,β-unsaturated aldehydes and the corresponding benzylic alcohols is reported. The new method provides a single-step access to these compounds for the first time. The applications of pyridinium p-toluenesulfonate (PPTS) as a very mild Brønsted acid catalyst and 5 Å molecular sieves (MS) as the dehydrating agent were found to be essential. Furthermore, an application of the acetals in the synthesis of 1-functionalized dienes is exemplified.

Key words

acetals - zeolites - molecular sieves - dienes - aldehydes

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