Chemistry of [(perfluoroalkyl)methyl] oxiranes. Regioselectivity of ring opening with O-nucleophiles and the preparation of amphiphilic monomers

Abstract The reactions of oxiranes R F CH 2 CH(–O–)CH 2 (R F ≡C 4 F 9 , C 6 F 13 , C 8 F 17 ; 4a – 4c ) with a series of alkanols in the presence of a Lewis acid took place at the terminal carbon atom with complete regioselectivity. 2-Hydroxyethyl methacrylate and acrylate reacted similarly. The reaction with alkane diols was controlled to proceed with one or two molecules of the oxiranes chemoselectively. Non-regioselective, base-catalysed ring opening by methacrylic acid (83% terminal attack) was discussed on the basis of the hard and soft acids and bases (HSAB) concept. A convenient transformation of the oxiranes to the corresponding diols 13a – 13c via dioxolane intermediates, and their conversion to bis-methacrylates, was accomplished with overall yields of 75%–79%. Thiourea converted the oxiranes into the corresponding thiiranes ( 15a – 15c ). The reactions afforded products generally in yields of 82%–98%.