Three-component coupling of carbonyl compounds, homoallylic alcohols, and nitrites has been achieved using 20 mol % of phosphomolybdic acid (PMA) at ambient temperature via the Prins-Ritter sequence to furnish 4-amidotetrahydropyrans in high yields with all cis selectivity. Spirocyclic-4-amidotetrahydropyrans are obtained using cyclic ketones. (C) 2008 Elsevier Ltd. All rights reserved.
Srinivasan; Perumal; Raja, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2011, vol. 50, # 8, p. 1083 - 1091