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Lewis Acidic Chloroaluminate Ionic Liquids: Novel Reaction Media for the Synthesis of 4-Chloropyrans

Jhillu S. Yadav *, Basi V. S. Reddy, Maddi Sridhar Reddy, Namelikonda Niranjan, Attaluri R. Prasad

*Division of Organic Chemistry, Indian Institute of Chemical Technology, Hyderabad 500 007, India, Email:

J. S. Yadav, B. V. S. Reddy, M. S. Reddy, N. Niranjan, A. R. Prasad, Eur. J. Org. Chem., 2003, 1779-1783.

DOI: 10.1002/ejoc.200210638


1-n-Butyl-3-methylimidazolium chloroaluminate [bmin]Cl . AlCl3 was successfully employed as a reaction medium for Prins cyclizations, to produce 4-chlorotetrahydropyran derivatives in short reaction times.

see article for more examples

proposed mechanism

The 'Aqueous' Prins Cyclization: A Diastereoselective Synthesis of 4-Hydroxytetrahydropyran Derivatives

J. S. Yadav, B. V. S. Reddy, G. G. K. S. N. Kumar, S. Aravind, Synthesis, 2008, 395-400.

Rapid and Efficient Protocol for the Synthesis of 4-Chlorotetrahydropyrans Using Niobium(V) Chloride

J. S. Yadav, B. V. Subba Reddy, M. K. Gupta, S. K. Biswas, Synthesis, 2004, 2711-2715.

Key Words

Alcohols, Aldehydes, Cyclization, Ionic liquids, Prins Reaction, Tetrahydropyrans

ID: J24-Y2003-130