7-Endo selenocyclization reactions on chiral 3-prenyl and 3-cinnamyl-2 hydroxymethylperhydro-1,3-benzoxazine derivatives. A way to enantiopure 1,4-oxazepanes

Abstract

Enantiopure 1,4-oxazepanes derivatives have been prepared by selenocyclofunctionalization of chiral 3-prenyl- and 3-cinnamyl-2-hydroxymethyl-substituted perhydro-1,3-benzoxazine derivatives. The 7-endo-cyclization occurs in high yields and diastereoselection. The regio and stereochemistry of the cyclization products was dependent of the substitution pattern of the double bond, the nature of the hydroxyl group and the experimental conditions.