Rapid and Efficient Protocol for the Synthesis of 4-Chlorotetrahydropyrans Using Niobium(V) Chloride
J. S. Yadav*, B. V. Subba Reddy, Manoj Kumar Gupta, Swapan Kumar Biswas
*Division of Organic Chemistry, Indian Institute of Chemical Technology,
Hyderabad-500007, India, Email: yadavpub
iict.res.in
J. S. Yadav, B. V. Subba Reddy, M. K. Gupta, S. K. Biswas, Synthesis, 2004, 2711-2715.
DOI: 10.1055/s-2004-831220
Abstract
Aldehydes undergo rapid and selective coupling with 3-buten-1-ol in the presence of 20 mol% of niobium(V) chloride to afford 4-chlorotetrahydropyran derivatives under extremely mild conditions in excellent yields. Similar halogenated tetrahydropyrans are also obtained using gallium(III) halides.
see article for more examples
proposed mechanism
Lewis Acidic Chloroaluminate Ionic Liquids: Novel Reaction Media for the Synthesis of 4-Chloropyrans
J. S. Yadv, B. V. S. Reddy, M. S. Reddy, N. Niranjan, A. R. Prasad, Eur. J. Org. Chem., 2003, 1779-1783.
Key Words
Prins reaction, niobium(V) chloride, gallium(III) halides, tetrahydropyrans
ID: J66-Y2004-2390
