Abstract
The reaction of dihydropyran (I) with N, N-dichlorbenzenesulfonamide (II) and that with N, N-dichlorobenzamide (III) were studied. The reaction of I with II gave trans-2-benzenesulfonamido-3-chlorotetrahydropyran (V) and a minor product which is a cis-isomer of V. In the reaction of I with III, trans-2-benzamido-3-chlorotetrahydropyran (VIII), its cis-isomer (IX), 2-ethoxy-3-chlorotetrahydropyran (X), and benzamide (XI) were obtained. The reactions of N-haloamides, II, III, and N, N-dibromobenzenesulfonamide, with dihydropyran were compared and the mode of them were discussed.
