Convenient synthesis of alpha-trifluoromethylated acyloins from alpha-hydroxy or alpha-amino acids.
Alpha-trifluoromethylated acyloins (2 and 6) have been prepared from alpha-hydroxy acids (1), N-acylprolines (5) or N-acyl-N-alkyl alpha-amino acids (8) by novel transformation reactions with trifluoroacetic anhydride (TFAA) in the presence of pyridine. The former reaction of 1 could proceed through mesoionic 1,3-dioxolium-4-olates, whereas the latter two reactions of alpha-amino acids (5 and 8) could involve mesoionic 1,3-oxazolium-5-olates. The reaction of 1 with TFAA shows more potential for practical applications because of the ready availability of the starting materials and ease of manipulation.
Kawase
M
M
Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan. kawasema@josai.ac.jp
Saito
S
S
Kurihara
T
T
D000089:Acetic Anhydrides; D000596:Amino Acids / Q000737:chemistry*; D005233:Fatty Alcohols / Q000138:chemical synthesis*; D005463:Fluoroacetates; D005559:Formamides; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis*; D006880:Hydroxy Acids / Q000737:chemistry*; D007202:Indicators and Reagents; D008333:Mandelic Acids / Q000737:chemistry
D000089:Acetic Anhydrides; D000596:Amino Acids; D005233:Fatty Alcohols; D005463:Fluoroacetates; D005559:Formamides; D006845:Hydrocarbons, Fluorinated; D006880:Hydroxy Acids; D007202:Indicators and Reagents; D008333:Mandelic Acids; C011159:acyloin; C017958:trifluoroacetic anhydride