Synthesis of γ-pyrone precursors by condensation of acetyl ketene dithioacetals with ethyl polyfluorocarboxylates and diethyl oxalate

2-Aryl-6-Polyfluoroalkyl-4-Pyrones as Promising RF-Building-Blocks: Synthesis and Application for Construction of Fluorinated Azaheterocycles

“…Despite the promising synthetic utility of CF 3 -bearing 4-pyrones, they remain to be hard-to-reach compounds [ 17 , 18 ]. The methods for the construction of 4-pyrones are actively developed, and in the literature there are three general approaches for the synthesis of 2-R F -4-pyrones based on (i) cyclization of tricarbonyl compounds or their derivatives prepared via Claisen condensation [ 19 , 20 , 21 , 22 ], (ii) cycloadditions of ketenes [ 23 , 24 , 25 ], and (iii) modification of substituted 2-R F -4-pyrones (usually for carboxylic acid derivatives) via side-chain transformations [ 26 ] ( Scheme 1 ). However, there are usually some limitations connected with the narrow scope of obtained pyrones, variation of the nature of the substituents in several positions of the pyrone ring, and preparation of 4-pyrones bearing long-chain polyfluoroakyl substituents.…”