Reaction of substituted sulfenes with N,N-disubstituted α-amino-methyleneketones. II. Synthesis of N,N-disubstituted cis and trans 4-amino-3-chloro-3,4,5,6,7,8-hexahydro-1,2-benzoxathiin 2,2-dioxides,and 4-amino-5,6,7,8-tetrahydro-1,2-benzoxathiin 2,2-dioxides

The polar 1,4-cycloaddition of chlorosulfene (generated in situ from chloromethanesulfonyl chloride and triethylamine) to N,N-disubstituted (E)-2-aminomethylenecyclohexanones I gave mixtures of N,N-disubstituted cis and trans 4-amino-3-chloro-3,4,5,6,7,8-hexahydro-1,2-benzoxathiin 2,2-dioxides III and IV, except for N,N-diphenyl enaminone which did not react. Only compounds IV could be separated from these mixtures by silica gel chromatography, with the exception of the piperidino adducts (III + IV)d, from which also IIId could be obtained pure. Compounds IV or mixtures III + IV were dehydrochlorinated with DBN in refluxing benzene to afford N,N-disubstituted 4-amino-5,6,7,8-tetrahydro-1,2-benzoxathiin 2,2-dioxides V in satisfactory yields. Structural and conformational features of compounds III, IV and V were determined from uv, ir and nmr spectral data.