Water-soluble phosphines: Part XII. Pd catalyzed PC coupling reactions: a novel synthetic route to cationic phosphines with para- and meta-guanidiniumphenyl moieties

Abstract Mono- and bifunctional guanidinium phosphines ( 3c , 4a , 4b , 5a – 5d , 5f ) containing para -and meta- guanidiniumphenyl moieties C 6 H 4 NH C(NH 2 )(NR 2 ) + (R=H, Me) are accessible in high yields by Pd catalyzed P C coupling reactions between iodophenyl guanidines I C 6 H 4 NH C(NH)NR 2 ( meta- , para -isomers; R=H, Me) and phenyl- or diphenylphosphine. The X-ray structure of 3c ·MeOH (space group P 2 1 2 1 2 1 ) has been determined, showing a planar guanidinium group in a NH O and NH Cl hydrogen bridged arrangement. Pd(II) and Mo(0) complexes of 5c have been synthesized. The influence of the cationic guanidinium group on the electronic and steric parameters of 5c is discussed. A comparative study of 5c , phosphonated and sulfonated phosphine ligands in the biphasic Pd catalyzed Suzuki-type coupling between m -bromophenyldiphenyl phosphine oxide and para -tolylboronic acid shows 5c to be less active than Ph 2 P C 6 H 4 4-PO 3 Na 2 .