Direct synthesis of tetrahydropyrans via one-pot Babier-Prins cyclization of allylbromide with carbonyl compounds promoted by RTILs BPyX/SnX′2 or BBIMBr/SnBr2

Tetrahydropyran compounds can be directly synthesized from allylbromide and carbonyl compounds by means of one-pot Babier-Prins cyclization promoted by BPyX/SnX'(2) or BBINBr/SnBr2 complex (functionalized RTILs) under solvent-free conditions. 2,6-Homo-bissubstituted- and 2,6,6-trisubstituted, especially 6-(spirocycloalkyl)-, tetralrydropyran compounds can be prepared in good yields. (c) 2006 Elsevier Ltd. All rights reserved.