Reaction of 2-Dialkylamino-1,3-oxathioran-2-ylium Salts with Nucleophilic Reagents

Reactions of 2-dialkylamino-1,3-oxathioran-2-ylium prechlorates [3], five-membered ring's trihetero-substituted carbonium salts, with several nucleophiles were carried out. As the results of these treatments, it turned out that [3] had ambident properties, and 2-position of [3] became hard electrophilic center and 5-position of [3] became soft electrophilic center. That is, hard bases such as hydroxide ion, alkoxide ion, and acetoxide ion attacked upon the 2-position, and soft bases such as p-tolylmercaptide ion, N, N-dimethyldithiocarbamate ion, isocyanate ion, and cyanide ion acttacked upon the 5-position according to the HASB-Rule. Furthermore, aniline, moderate base, attacked upon the 2-position.