3-Trifloxypropene iminium and propyne iminium salts derived fromN-Allyl-,N-Homoallyl-, and N-benzyl-substituted semicyclic enaminones

✍ Scribed by R. Neumann; H.G. Herz; G. Maas

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 61 KB
• Volume: 341
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/(sici)1521-3897(199902)341:2<121::aid-prac121>3.0.co;2-d

✦ Synopsis

Propyne iminium salts have been recognized as useful synthetic building blocks in organic synthesis. Most importantly, they can be transformed into functionalized and highly substituted propargylamines, aminoallenes, and amino-1,3-butadienes . In earlier papers [5 -7], we have described that propyne iminium salts III are easily available by O-sulfonylation of enaminoketones I with triflic anhydride (Tf 2 O), followed by elimination of triflic acid (HOTf) from the resulting 3-trifloxypropene iminium triflates II (Scheme 1). Elimination of HOTf from salts II is achieved by heating them in acetonitrile solution, by vacuum thermolysis, or with the help of tertiary amines.