Novel Synthesis of ω-(Diphenylphosphinyl)alkylcarboxylic Acids from Triphenyl-ω-carboxyalkylphosphonium Salts

Article abstract of DOI:10.1021/jo01299a040

A novel method for the synthesis of triphenylphosphonium salts of the type (C6H5)3P⁺(CH2)nCO2H,X^- (1: n=2,3; X=Cl; n=5,10,11; X=Br) from the corresponding ω-haloalkylcarboxylic acids and triphenylphosphine has been described.When members of 1 were treated with NaH/Me2SO/THF at room temperature under N2, the corresponding ω-(diphenylphosphinyl)alkylcarboxylic acids 2 (n=3,5,10,11) were isolated.The yields were good (62-75percent) for compounds with longer side chains (n=10,11).In one case (n=3), (C6H5)3P was isolated as a side product (yield 20percent).Attempts to prepare the Wittig reagents from 1 and the subsequent reaction with aldehydes (benzaldehyde and 9-anthraldehyde) failed to yield the expected alkenes.However, members of 2 were produced, and it was possible to recover >90percent of the unreacted 9-anthraldehyde.The structures of the compounds in the series 1 and 2 have been established via the spectral properties and elemental analyses.The 31P and 13C chemical shifts as well as C-P coupling constants have been evaluated and analyzed.A tentative mechanism has been proposed for the formation of 2 from 1.