Process for producing fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate

#The present invention relates to a process for producing a fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate represented by the general formula [3], which is useful as a monomer for a next-generation photoresist:

#where R1 is a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tertbutyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group or perfluoroethyl group; and R2 is a fluorine-containing alkyl group having a carbon number of 1 to 6.

#Sulfonylaminoethyl α-substituted acrylates are expected to be useful as monomers for next-generation photoresists. Photoresist materials, when synthesized using sulfonylaminoethyl α-substituted acrylates as photoresist monomers, are provided with excellent light transparency and surface adsorptivity as reported in U.S. Pat. No. 6,165,678 (hereinafter referred to as “Patent Document 1”). In Patent Document 1, however, there is no detailed description about the synthesis of a fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate represented by the formula [3], which is a target compound of the present invention. Patent Document 1 merely discloses a process for synthesizing a sulfonylaminoethyl α-substituted acrylate in a broad sense by condensation of the corresponding sulfonylaminoethanol with α-substituted acryloyl chloride. It is further reported in Japanese Laid-Open Patent Publication 2005-281301 (hereinafter referred to as “Patent Document 2”) that the synthesis process of Patent Document 1 is not suitable for the synthesis of a fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate.

#The present invention will be described in more detail below.

#In the present invention, the fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate of the formula [3] is produced by sulfonamidation reaction between the aminoethyl α-substituted acrylate of the formula [1a] and the fluorine-containing alkylsulfonic fluoride of the formula [2], or by sulfonamidation reaction between the aminoethyl α-substituted acrylate salt of the formula [1b] and the fluorine-containing alkylsulfonic fluoride of the formula [2] in the presence of a base, using the fluorine-containing compound as the reaction solvent. It is possible to accelerate the sulfonamidation reaction of the aminoethyl α-substituted acrylate [1a] or aminoethyl α-substituted acrylate salt [1b] and the fluorine-containing alkylsulfonic fluoride [2] by the use of the fluorine-containing compound as the reaction solvent. Thus, the production process of the present invention provides a much higher yield of the fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate [3] than conventional production processes even under moderate temperature conditions and can be advantageously applied to the industrial production of the fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate [3].

#In the target fluorine-containing alkylsulfonylaminoethyl α-substituted acrylate [3], the substituent R1 is a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tertbutyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group or perfluoroethyl group whereas the substituent R2 is a fluorine-containing C1-C6 alkyl group, preferably fluoromethyl group, difluoromethyl group, perfluoroethyl group, n-perfluoropropyl group or n-perfluorobutyl group. The reaction substrates [1a], [1b] and [2] can be thus selected appropriately depending on the substituents R1 and R2 of the target reaction product [3]. In view of the usability of the reaction product [3], it is preferable that the substituent R1 is methyl and the substituent R2 is trifluoromethyl.