Synthesis and Reactions of (2,2,2‐Trifluoroethyl)triphenylphosphonium Trifluoromethanesulfonate

(2,2,2‐Trifluoroethyl)triphenylphosphonium trifluoromethanesulfonate (triflate) ( 1 ) was readily synthesized in high yield from triphenylphosphane and 2,2,2‐trifluoroethyl triflate. The Wittig olefination of 1 with aromatic aldehydes bearing electron‐withdrawing groups with CsF as a base in DMF proceeded cleanly, producing the corresponding 3,3,3‐trifluoropropenylidene compounds in good yields. On the other hand, the hydrolysis of 1 in methanol containing sodium hydroxide gave (2,2‐dimethoxyvinyl)triphenylphosphonium triflate ( 6a ) in high yield instead of the corresponding (2,2,2‐trifluoroethyl)diphenylphosphane oxide. Furthermore, reactions between 1 and secondary amines exclusively gave the novel ( Z )‐(2‐amino‐2‐fluorovinyl)triphenylphosphonium triflates ( 10 ) in high yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)