A Facile Synthesis of 4-Aryl-1,1,1-trifluorobut-3-en-2-ones via 4-Aryl Substituted CF3 - Containing Dihydropyran Derivatives: A Versatile Method for the Introduction of Fluorine-Containing C4- and C6-Unit to Aromatic Compounds
作者:Etsuji Okada、Norio Ota、Dai Shibata、Satoru Adachi、Shohei Saikawa
DOI:10.3987/com-09-s(s)60
日期:——
The CF3 - containing dihydropyran derivative (2) reacted easily with various aromatic compounds in trifluoroacetic acid to give novel 4-aryl substituted dihydropyran derivatives (7) in moderate to high yields. Retro hetero Die Is-Alder reaction of thus obtained 7 proceeded readily by heating at 300 degrees C to afford the corresponding 4-aryl-1,1,1-trifluorobut-3-en-2-ones (12) in good to excellent yields. With the use of p-toluenesulfonic acid instead of trifluoroacetic acid together with dihydropyran (2) in acetonitrile, 4-trifluoroacetyl-1,3-butalienylation of 1,3-dimethoxybenzene occurred successfully. The bimolecular reaction of dihydropyran (2) in the presence of p-toluenesulfonic acid was also examined.