[1-(Trimethylsiloxy)alkyl]triphenylphosphonium salts: Syntheses and utilization, comparisons with analogous pyridinium salts

Article abstract of DOI:10.1055/s-1992-26168

Three-component reactions with aldehydes, trimethylsilyl trifluoromethanesulfonate or iodide, and triphenylphosphine (TPP) yield the title compounds. The X-ray structure of the cationic part of a representative product, the (4-methylphenyl)[(trimethylsiloxy) methyl]TPP⁺, shows an interesting lengthening of the P⁺-C(α) bond compared with reported values for methyl(TPP)⁺ and benzyl(TPP)⁺ cations (C(α) represents the P-bonded carbon atom of the various alkyl groups). The behavior of the title compounds towards charged nucleophilic reagents and a powerful electrophile (trifluoromethanesulfonic anhydride) is similar to that of analogous pyridinium salts.