Synthesis of Polyfluorinated Alkynes, Novel Building Blocks for Fluorous Chemistry

Abstract

Ethynyldimethylphenylsilane (2) was lithiated with butyllithium and reacted with (perfluorohexyl)ethyl triflate (1) to afford silylated 4-(perfluorohexyl)butyne 3, which was deprotected with potassium fluoride to give 4-(perfluorohexyl)butyne 4. Lithiation of fluoroalkyne 4 with butyllithium followed by the addition of polyfluoroalkyl triflate 1 furnished bis(perfluorohexyl)butyne 5 in a moderate yield. Polyfluoroalkylated alkynes 3, 4 and 5 are perspective building blocks for fluorous chemistry, the sufficient nucleophilic properties of which are preserved by one or two ethylene spacers between the triple bond and perfluoroalkyl group(s).