Addition-rearrangement reactions of N-(arylsulphonyloxy)amines and 3,4-dihydro-2H-pyran
Abstract
A series of N-alkyl-O-(arylsulphonyl)hydroxylamines (NSA) was treated with 3,4-dihydro-2H-pyran (DHP). Acid-catalysed addition to the double bond followed by cationic rearrangement gave cyclic imidates from hydride migration (major) and ring expansion (minor), which were reduced to amino alcohols for analysis. The results indicate that NSA function as nucleophiles which capture the oxonium ion produced by protonation of DHP, and give new NSA derivatives that rearrange to the observed products.