Catalysed prototropic rearrangements. Part 3. Metal carbonyl-catalysed lsomerization of N-allylsulphonamides to N-prop-2-enyl and N-propylidene derivatives

N-Allylsulphonamides (4) are readily isomerized in the presence of pentacarbonyliron upon irradiation by u.v. light. N-Prop-2-enyl derivatives (5) are obtained, and further isomerization under suitable conditions leads to N-propylidenesulphonamides (6). The last reaction proceeds by a specific 1,3-proton migration involving an NH group as shown by isotopic labelling experiments. © 1977 by The Chemical Society.