Abstract
The high-yielding synthesis of a wide variety of 1,3-dioxanes via the Prins reaction under mild conditions has been demonstrated using Brønsted-acidic imidazolium ionic liquid [bmim(SO3H)][OTf] or bmimOTf. The use of ionic liquid makes this synthesis simple, convenient, cost-effective, and environmentally friendly. Furthermore, bmimOTf was conveniently separated from the products and can be easily recycled for the Prins reaction with excellent yields. This method works well with a variety of aliphatic aldehydes including formaldehyde, acetaldehyde, propionaldehyde, and cyclohexanecarboxaldehyde.
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GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
The authors thank the University Sophisticated Instrument Center, KUD, for IR, GC, GC-MS, and 1H and 13C NMR. The authors also thank M. V. Kulkarni for useful discussion.
Notes
a Conversion based on GC-MS analysis.
b Isolated yields of pure products; NI: no isolation.
c Reaction was carried out in bmimOTf (in absence of MeCN).
a Isolated yields of pure products; NR; no reaction.
b The reactions were carried out with recycled bmimOTf, cycle 1.
c The reactions were carried out with recycled bmimOTf, cycle 2.
d The reactions were carried out with recycled bmimOTf, cycle 3.