Cycloaddition Reaction of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates with Enamines Affording 2-Trifluoroacetylpyrroles
作者:Ryosuke Saijo、Masami Kawase
DOI:10.1002/ejoc.201801728
日期:2019.2.21
Mesoionic 4‐trifluoroacetyl‐1,3‐oxazolium‐5‐olates (münchnones) reacted with enamines to yield densely functionalized 2‐trifluoroacetylpyrroles. The trifluoroacetic acid addition in the reaction was the key for the good yields of the 1,3‐dipolar cycloaddition product. DFT calculations were performed for the 1,3‐dipolar cycloadditions of münchnones and enamines.
Cyclocondensation Reaction of Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates with Hydroxylamine affording 6-Trifluoromethyl-5,6-dihydro-4H-1,2,4-oxadiazin-6-ols
Mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1) undergo tandem addition of hydroxylamine to afford 6-trifluoromethyl-1,2,4-oxadiazin-6-ols (3) in high yields.
Heterocyclization of 4-Trifluoroacetyl-1,3-oxazolium-5-olates with 1,4-Bis-nucleophiles
Reactions of aromatic 1,4-bis-nucleophiles such as o-phenylenediamine and o-aminothiophenol, with mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1) gave regiospecifically seven member trifluoromethylated heterocycles such as 1,5-benzodiazepines (3) and 1,5-benzothiazepines (4). The reaction with o-aminophenol afforded non-cyclized products (5). The structures of 3, 4, and 5 were established by X-Ray diffraction analysis.
Synthesis of Functionalized Pyrrolidines from Mesoionic 4-Trifluoroacetyl-1,3-oxazolium-5-olates and Aminomalonate
作者:Masami Kawase、Hiroshi Miyamae、Setsuo Saito
DOI:10.3987/com-98-s(h)46
日期:——
Mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1) undergo tandem addition of aminomalonate to afford 3-amido-4-trifluoromethylpyrrolidin-2-ones (2) in moderate yields.