Syntheses and characterization of bis(trifluoromethyl)phosphino naphthalenes and acenaphthenes

Syntheses of heteroleptic 1,8-bis(phosphino)naphthalenes and 5,6-bis(phosphino)acenaphthenes were attempted using several synthetic strategies. Reaction of aryllithium with triphenylphosphite gave ArP(OPh)(2) (Ar = substituted naphthalene or acenaphthene), which was transformed into ArP(CF3)(2), using a nucleophilic trifluoromethylation reaction with Me3SiCF3/CsF. The importance of the correct choice of solvent for the trifluoromethylation reactions is discussed. The incompatibility of ArP(CF3)(2) with organolithium hampered the attachment of the second phosphine functionality to the organic backbone. Tetraphenoxyethylene was obtained in a small amount as a side product in the trifluoromethylation reaction. Selected new compounds were characterized by single-crystal X-ray diffraction.