Stereoselective Formation of<i>trans</i>-2,5-Disubstituted Tetrahydropyrans by Intramolecular Nucleophilic Substitution and a Computational Study at the AM1 Level
The synthesis of 2,5-disubstituted tetrahydropyrans bearing a hydrophobic moiety at the C5 position from (E)- and (Z)-7-hydroxy-6-substituted 2,3-unsaturated esters by way of intramolecular nucleophilic substitution proceeded with high stereoselectivity. A theoretical study at the AM1 level of the cyclization reaction suggested that the reaction is kinetically controlled and that the preferred path