CeCl3•7H2O/AcCl-catalyzed Prins-Ritter reaction sequence:: a novel synthesis of 4-amido tetrahydropyran derivatives

Homoallylic alcohols, carbonyl compounds and nitriles undergo a smooth tandem Prins-Ritter type cyclization in the presence Of CeCl(3)(.)7H(2)O/AcCl at ambient temperature to produce 4-amido tetrahydropyrans in high yields with all cis-selectivity. Spirocyclic 4-amido tetrahydropyrans are obtained in the case of cyclic ketones. (c) 2007 Published by Elsevier Ltd.