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Synfacts 2008(7): 0682-0682  
DOI: 10.1055/s-2008-1078473
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 4-Iodopiperidines via Aza-Prins Cyclization

Contributor(s): Victor Snieckus, Jignesh J. Patel
J. S. Yadav*, B. V. Subba Reddy, D. N. Chaya, G. G. K. S. Narayana Kumar, S. Aravind, A. C. Kunwar, C. Madavi
Indian Institute of Chemical Technology, Hyderabad, India
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Publication History

Publication Date:
20 June 2008 (online)

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Significance

Presented here is a one-step, three-component synthesis of 2-mono- and 2,6-disubstituted 4-iodopiperidines from homoallylic amines and aldehydes via aza-Prins cyclization using a catalytic amount of gallium(III) iodide and stoichiometric iodine. Excellent trans selectivity was observed for the formation of 2,4-disubstituted piperidines. Substituted homoallylic amines afforded 2,4,6-trisubstituted piperidines with all cis configuration. Other metal iodides (In, Al, Mg) with iodine (1 equiv) gave slightly lower yields. Catalytic FeCl3 (10 mol%) with iodine (1 equiv) gave 4-iodopiperidines along with 4-chloropiperidine products.