Direct phosphonylation of aromatic azaheterocycles.

Revisiting the Hirao Cross-coupling: Improved Synthesis of Aryl and Heteroaryl Phosphonates

Advances and New Variations of the Hirao Reaction

Five new metal pyridylphosphonate polymers have been prepared, fully characterized, and their room-temperature luminescence probed. The reaction of (2-pyridyl)phosphonic acid (2pypo) with ZnX2 (X = Br, Cl) afforded two-dimensional polymers [Zn(X)(2pypo)]n {X = Cl = (1), X = Br = (2)}, which feature cyclic 12-membered Zn–O–P cores that are interlinked by bridged oxygen atoms from the phosphonate moiety. From the room–temperature, aqueous reactions of 2pypo and the corresponding metal salts, the one-dimensional polymers [Cd(μ-Cl)2(2pypo)]n (3) and [Hg(2pypo)]n (4) were isolated in moderate yield. The one-dimensional structure of 3 is supported through bridging chlorides and two η2-phosphonate oxygen atoms, while 4 is a highly symmetrical polymer that exhibits pyridyl nitrogen coordination to the mercury center and uses two μ2-oxygen atoms to polymerize. Reaction of silver triflate (CF3SO3Ag) with 2pypo afforded a crystalline silver polymer that displays a zig-zag arrangement of silver atoms with argentophilic interactions and that is stablized through bridged triflate and phosphonate moieties. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

A Mild Synthetic Route to Zinc, Cadmium, and Silver Polymers with (2‐Pyridyl)phosphonic Acid: Synthesis and Analysis

The reactions of AlCl3·6H2O and GaCl3 with 2-pyridylphosphonic acid (2PypoH2) and 4-pyridylphosphonic acid (4PypoH2) afford cyclic aluminum and gallium phosphonate structures of [(2PypoH)4Al4(OH2)12]Cl8·6H2O (1), [(4PypoH)4Al4(OH2)12]Cl8·11H2O (2), [(2PypoH)4Al4(OH2)12](NO3)8·7H2O (3), [(2PypoH)2(2Pypo)4Ga8Cl12(OH2)4(thf)2](GaCl4)2··8thf (4), and [(2PypoH)2(2Pypo)4Ga8Cl12(OH2)4(thf)2](NO3)2·9thf (5). Structures 1−3 feature four aluminum atoms bridged by oxygen atoms from the phosphonate moiety and show structural resemblance to the secondary building units found in zeolites and aluminum phosphates. The gallium complexes, 4 and 5, have eight gallium atoms bridged by phosphonate moieties with two GaCl4− counterions present in 4 and nitrate ions in 5. The cage structures 1−3 are interlinked by strong hydrogen bonds, forming polymeric chains that, for aluminum, are thermally robust. Exchange of the phosphonic acid for the more flexible 4PyCH2PO3H2 afforded a coordination polymer with a 1:1 Ga:P ratio, {[(4PyC...

Convenient synthesis of aluminum and gallium phosphonate cages.

Our aim was to study the aromatic nucleophilic substitution between the sodium anion of diethylphosphite and several halogenated substrates like: iodo-anilines, iodo-nitrobenzenes, bromo- and iodopyridines, bromoquinoline. Two coupling processes have been evaluted. The first one is the photostimulated nucleophilic substitution (SRN1), the second the promoted arylation by transition metals. We obtain good results with the first method which is efficient and simple; by contrast the second one has given only few positive results. We describe five aromatic aminophosphonic acids. Nous avons etudie la substitution nucleophile aromatique entre le diethylphosphite sode et plusieurs substrats halogenes tels que iodo-anilines, iodonitrobenzenes, bromo- et iodo-pyridines, bromo-quinoleine. Deux methodes de couplage ont ete evaluees. L'une est la substitution nucleophile sous photostimulation (SRN1), l'autre l'assistance par les metaux de transition. La premiere donne de bons resultats dans la majorite des c...

Preparation d'aminophenyl-, nitrophenyl-, pyridyl-, et quinolylphosphonates sous photostimulation ou assistance metallique; acces aux acides aminophosphoniques correspondants

J. J. Bulot

Papers

Preparation d'aminophenyl-, nitrophenyl-, pyridyl-, et quinolylphosphonates sous photostimulation ou assistance metallique; acces aux acides aminophosphoniques correspondants