Enaminosulfones from 3-Trifloxypropene Iminium Salts: A 1,5(O5C) Trifluoromethylsulfonyl Shift*
نویسندگان
چکیده
Triflic anhydride (Tf2O) is the reagent of choice for the introduction of the trifluoromethylsulfonyl (CF3SO2) group into a variety of organic substrates, and the resulting compounds often have a unique chemical reactivity [1]. A case in point is given by 3-trifloxypropene iminium triflates which are obtained by O-sulfonylation of enaminones with Tf2O [2, 3] and which are suited for transformations that are not known for related [4] 3chloropropene iminium salts. 3-Trifloxypropene iminium triflates are susceptible to nucleophilic substitution [2, 5], can be involved in intra[6] und intermolecular [7] aromatic substitution reactions, and can be transformed into a wide range of propyne iminium triflates by -elimination of triflic acid [6, 8, 9]. The latter transformation is either achieved with the help of a tertiary amine base or under purely thermal conditions. In this communication, we report that certain semicyclic 3-trifloxypropene iminium triflates upon treatment with an amine base do not yield propyne iminium triflates but are converted into enaminosulfones.
منابع مشابه
Synthesis of a family of 3-alkyl- or 3-aryl-substituted 1,2-dihydroquinazolinium salts and their isomerization to 4-iminium-1,2,3,4-tetrahydroquinolines.
A straightforward synthesis of substituted 1,2-dihydroquinazolinium triflates (3) is reported by reaction of 2-imino-substituted anilines with a range of carbonyl compounds in the presence of triflic acid via intermediate iminium salts. Similar reactions with di- or trialdehydes and triflic acid give bis- or tris-(1,2-dihydroquinazolinium) salts. Some 4-methyl substituted 1,2-dihydroquinazolini...
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