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The first section of this work was dedicated to the development of nucleophilic phosphination reactions on aromatic fluoro compounds. Phosphino- derivatives of the α-amino acids phenylglycine and phenylalanine have been obtained by reaction of the potassium- salts of 2, or 4-fluorophenylglycine- or alanine respectively with KPPh₂ using DME as solvent. The x-ray structural analysis of 1 reveals the bulky nature of the PPh₂- substituent in ortho position to the amino acid substituent and the betaine type structure in the α-amino acid moiety of 1. Derivatives of 2-diphenylphosphino-phenylglycine 1, bearing N-, O-, P- protecting groups have been synthesed and investigated. N-acetyl protected amino acid 9 was accessible by reaction of 1 with Ac₂O in good yields. The methylester 10 was obtained by using equimolar amounts of HC(OMe)₃/ CF₃COOH/ MeOH. Due to the low solubility of 1 in solvents like toluene its reaction with sulphur failed, the phosphine oxide 11 was easily accessible by oxidation of 1 with H₂O₂. A new synthetic approach to the aldehyde 15 has been developed using acetal protected 2-fluorobenzaldehyde and KPPh₂. 15 was obtained in 85 % overall yield. Base catalysed reaction of the aldehyde 15 with HP(O)(OMe)₂ and HP(O)Me₂ afforded the α-hydroxyphosphonic acid compound 16 and the phosphine oxide 17. The analogous α-aminophosphonic acid and phosphanoxide have been obtained by reaction of the aldimine 18 with HP(O)(OEt)₂ and HP(O)Me₂. Wittig reaction of 15 with Ph₃P=CHCO₂Me yielded the cinnamic ester 22. The alkali metal salts of the cinnamic acid 23 show an unusual high solubility in water (> 500 g 23 in 1000 g H₂O at ambient temperature). Using KOᵗBu/DME as deprotonation agent twofold arylation of 2-pyridylphosphine with F-C₆H₄-SO₃K was possible and afforded ligand 24 with a surprisingly low solubility in water. The molecular structure of 24 has been determinated by x-ray structural analysis. The second part of this work was concerned with the development of new synthetic methologies for derivatives of triphenylphosphine bearing +M/ +I substituents like OH, NH₂, alkyl which were not accessible by nucleophilic phosphination of fluoro aromatic compounds. Prompted by literature reports a novel type of catalytic P-C cross coupling reaction was discovered. Reaction of secondary phosphines (PhPHR, R= Ph, CH₃) with functionalized iodo aromatic compounds in presence of catalytic amounts of Pd(OAc)₂ afforded tertiary phosphines bearing a wide range of different substituents. The reaction was found to be independent of the electronic nature of the substituents. A multitude of triphenylphosphine derivatives ((o, m, p)-Ph₂PC₆H(4-n)-Rₙ R= CH₃, NH₂, OH, CO₂Me, CH₂OH, NHC(NH₂)₂⁺) and heteroaromatic substituted phosphines have been synthesised in excellent yields. By arylation of primary phosphines (RPH₂, R= aryl, alkyl) with one equivalent of the iodo compound secondary phosphines could be obtained selectively. Arylation reactions with secondary phosphines were catalysed by using 0.01 to 0.1 mol% Pd(OAc)₂. For the corresponding reactions with PhPH₂ and other primary phosphines a palladium(0)complex formed by Pd₂(dba)₃ with equimolar amounts of a chelating ligand like dppp has been employed. Using this method triphenylphosphine ligands bearing hydrophilic guanidinium moieties have been obtained by reaction of iodophenylguanidines with PhRPH (R= H, Ph) in excellent yields. The structure of the guanidinium phosphines has been revealed by structural analysis and multinuclear NMR- spectroscopy including 15N-NMR- spectroscopy.