title: Water Soluble Cationic Phosphine Ligands Containing m-Guanidinium Phenyl Moieties. Syntheses and Applications in Aqueous Heck Type Reactions.
abstract: Cationic phosphine ligands containing m-guanidinium phenyl substituents {Ph(3-n)P[C(6)H(4)-m-NHC(NH(2))(NMe(2))](n)}(n+) nCl(-) (n = 1-3) (17a-c) have been obtained by addition of dimethylcyanamide to the amino groups of tertiary (m-aminophenyl)phosphines in acidic medium. The tertiary (m-aminophenyl)phosphines Ph(3-n)P(C(6)H(4)-m-NH(2))(n) (4a-c) were prepared by reaction of (3-[N,N-bis(trimethylsilyl)amino]phenyl)magnesium chloride (1) with chlorophosphines Ph(3-n)PCl(n) followed by deprotection of the bis(trimethylsilyl)amino groups with methanol. Using a similar protected group synthesis as above, the secondary (m-aminophenyl)phosphine Ph(H)PC(6)H(4)-m-NH(2) (7) could be prepared as well. It may be employed as a building block for the syntheses of chiral bidentate phosphine ligands (11, 14, and 15) bearing m-aminophenyl substituents. The guanidinium phosphines 17b and 17c are readily soluble in water. A comparative study of 17b and 17c, the aryl alkyl guanidinium phosphines 18 and 19, and TPPTS (P(C(6)H(4)-m-SO(3)Na)(3)) in the aqueous phase palladium-catalyzed C-C coupling reaction between p-iodobenzoate and (trifluoroacetyl)propargylamine shows 17b to be of surmounting activity.
authors.affiliation: Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
authors.forename: Antonella
authors.initials: A
authors.lastname: Hessler
authors.forename: Othmar
authors.initials: O
authors.lastname: Stelzer
authors.forename: Harald
authors.initials: H
authors.lastname: Dibowski
authors.forename: Karin
authors.initials: K
authors.lastname: Worm
authors.forename: Franz P.
authors.initials: FP
authors.lastname: Schmidtchen