A. Hessler et al., WATER-SOLUBLE CATIONIC PHOSPHINE-LIGANDS CONTAINING M-GUANIDINIUM PHENYL MOIETIES - SYNTHESES AND APPLICATIONS IN AQUEOUS HECK TYPE REACTIONS, Journal of organic chemistry, 62(8), 1997, pp. 2362-2369
Cationic phosphine ligands containing m-guanidinium phenyl substituent
s {Ph3-nP[C6H4-m-NHC(NH2)(NMe2)](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 Ph3-nP(C6H4-m-NH2)(n) (4a-c) were prepared by r
eaction of (3-[N,N-bis(trimethylsilyl)amino]phenyl)magnesium chloride
(I) with chlorophosphines Ph3-nPCln followed by deprotection of the bi
s(trimethylsilyl)amino groups with methanol. Using a similar protected
group synthesis as above, the secondary (m-aminophenyl)phosphine Ph(H
)PC6H4-m-NH2 (7) could be prepared as well. It may be employed as a bu
ilding block for the syntheses of chiral bidentate phosphine ligands (
11, 14, and 15) bearing m-aminophenyl substituents, The guanidinium ph
osphines 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(C6H4-m-SO3Na)(3)) in the aqueous phase palladium-catalyzed C-
C coupling reaction between p-iodobenzoate and (trifluoroacetyl)propar
gylamine shows 17b to be of surmounting activity.