José-Antonio Abad

Synthesis and Reactivity of 2-Aminophenylpalladium(II) Complexes: Insertion Reactions of Oxygen and Carbon Monoxide into Carbon−Palladium Bonds—New Examples of “Transphobia”

Insertion of CO into 2-aminophenylpalladium complexes leads to 2-aminobenzoylpalladium derivatives. When these compounds are forced to coordinate a carbon donor and a phosphane ligand in the trans position, a C−P coupling process or an insertion of oxygen occurs (see scheme). In this case, a dinuclear palladium complex containing a bridging anthranilato ligand is isolated.

Palladium-assisted formation of carbon-carbon bonds. Stoichiometric synthesis of indenols and indenones. Catalytic synthesis of an indenol

Reactions of diphenylacetylene or dimethylacetylenedicarboxylate with Q2[Pd2R2Cl2(μ-Cl)2] (1) [Q = (PhCH2)Ph3P; R = 2,3,4-trimethoxy-6-formylphenyl] give metallic palladium and 2,3-diphenyl-, or 2,3-dimethylcarboxylate-, 5,6,7-trimethoxyindenone (2 or 3), respectively whereas diphenylacetylene reacts with [PdR(bipy)(MeCN)]ClO4 (4), to give 2,3-diphenyl-5,6,7-trimethoxyindenol (5) and [Pd2 (OH)2(bipy)2](ClO4)2 (6). Catalytic synthesis of 5 is achieved by reaction of [HgR2], Ph2C2, and CuCl2 in the presence of (Me4N)2[Pd2Cl6] (molar ratios 1:2:2:0.1).

Synthesis and reactivity of (2-amine-5-nitrophenyl)platinum(II) complexes

Abstract Reaction of [HgR 2 ] (R = C 6 H 3 NH 2 -2, NO 2 -5) with [PtCl 2 (COD)] (COD = cycloocta-1,5-diene) yields cis -[PtCl(R)(COD)], which reacts with PPh 3 to give trans -[PtCl(R)(PPh 3 ) 2 ]. The latter reacts with AgClO 4 to give solutions from which the complexes trans -[PtI(R)(PPh 3 ) 2 ] or trans -[Pt(CO)(R)(PPh 3 ) 2 ]CIO 4 can be isolated. Treatment of some of these complexes with acetic anhydride gives the 2-acetamido-5-nitrophenyl (R*) derivatives [PtCl(R*)L 2 ] (L 2 = COD, L = PPh 3 ), and these, in turn react with AgClO 4 to give complexes cis [Pt(R*)L 2 ]ClO 4 in which the R* group acts as a chelating ligand. The main features of the structures of these complexes have been established by IR and NMR spectroscopy.

Mercuriation of 3,4,5-trimethoxybenzoic acid. Synthesis of derivatives of the mercuriation product and crystal and molecular structure of PPh3(CH2Ph)][HgCl{C6H(CO2)-6-(OMe)3-2,3,4}]

Abstract The mercuriation of 3,4,5-trimethoxybenzoic acid has been re-investigated and the product [HgCl{C 6 H(CO 2 H)-6-(OMe) 3 -2,3,4}] ( 1 ) characterized. It is deprotonated by Na 2 CO 3 to give [Hg{C 6 H(CO 2 )-6-(OMe) 3 -2,3,4}] n ( 2 ) which, in turn, reacts with benzyltriphenylphosphonium chloride or triphenylphosphine to give [PPh 3 (CH 2 Ph)][HgCl{C 6 H(CO 2 )-6-(OMe) 3 -2,3,4}]( 3 ) or [Hg{C 6 H(CO 2 )-6-(OMe) 3 -2,3,4}(PPh 3 )] ( 4 ), respectively. The reaction of 2 with MeI in the presence of [NMe 4 ]Cl affords [Hg{C 6 H(CO 2 Me)-6-(OMe) 3 -2,3,4} 2 ] ( 5 ), which reacts with HgCl 2 or HgCl 2 to give [HgX{C 6 H(CO 2 Me)-6-(OMe) 3 -2,3,4}] [X  Cl ( 6 ), I ( 7 )]. The crystal structure of 3 shows a linear geometry at the mercury atom [ClHgC 178.0(2)°, HgCl 2.315(2), HgC 2.060(5) A], with an additional long Hg⋯O contact [2.573(4) A].

Palladium-assisted formation of carboncarbon bonds Part 2. Stoichiometric synthesis of spirocyclic compounds. X-ray structure of a π-allylic palladium intermediate

Abstract Stoichiometric reactions of arylpalladium compounds with alkynes give spirocyclic organic and organometallic compounds. The compound bis{ k 2 -C-O-(2,3,4-trimethoxy-6-acetyl-phenyl)}di(μ-chloro)dipalladium(II) reacts with diphenyl-acetylene or ethyl 3-phenylpropiolate giving 6-acetyl-1,2,3,4-tetraphenyl-9,10-dimethoxy-spiro[4.5] 1,3,6,9-decatetraen-8-one and 6-acetyl-1,3-dicarboxyethyl-2,4-diphenyl-9,10-dimethoxy-spiro[4,5]1,3,6,9-decatetraen-8-one, respectively. A π-allylpalladium complex, η 3 -{6-acethyl-1,2,3,4-tetraphenyl-8,9,10-trimethoxy-spiro[4,5] 1,3,9-decatrien-6-enyl} (2,2′-bipyridine)palladium(II) trifluoromethylsulfonate solvated, with one molecule of 1,2-dichloroethane, has also been isolated and its structure determined by X-ray diffraction studies.

Palladium-assisted rearrangement of HC(O)C6H2(OMe)3-3,4,5 to HC(O)C6H2(OMe)3-2,3,4. X-Ray structures of [PdR(PPh3)(bipy)](CF3SO3)[R = C6H(CHO)-6,(OMe)3-2,3,4 and C6H(CHO)-2,(OMe)3-3,4,5; bipy = 2,2′-bipyridyl]

The anionic complex [Pd2R2Cl2(µ-Cl)2]2–{1, R = C6H(CHO)-6,(OMe)3– 2,3,4} and the neutral [Pd2R′2(µ-Cl)2]{2, R′= C6H(CHO)-2,(OMe)3-3,4,5} are both obtained by reaction of HgR2 with appropriate palladium precursors; the isomerization of R to R′ was confirmed by X-ray studies of the derivatives [PdR(PPh3)(bipy)](CF3SO3)5 and [PdR′(PPh3)(bipy)](CF3SO3)5′.

Non-arylic diorganothallium derivatives obtained by metallation. Synthesis and isolation of the first diketonylthallium(III) complexes

Addition of trifluoroacetic or trifluoromethanesulfonic acid to solution of thallium(III) trifluoroacetate in acetone results in formation of the compounds [Tl{CH2C(O)Me}2X](X = CF3CO21a or CF3SO31b. Compound 1b reacts in a 1 : 1 ratio with LiCl or KBr giving the halogeno derivatives [Tl{CH2C(O)Me}2Y](Y = Cl 2a or Br 2b). Compound 2a reacts with [N(PPh3)2]Cl yielding the anionic complex [N(PPh3)2][Tl{CH2C(O)Me}2Cl2]3. The reaction of 1b with 2,2′-bipyridine (bipy) gives [{Tl[CH2C(O)Me]2(µ-CF3SO3)(bipy)}2]4 in which each thallium atom has a distorted six-co-ordination with the acetonyl ligands in trans positions and two cis positions occupied by two bridging triflate anions.

The first ligand-assisted stereoselective Wittig reactions. Synthesis and crystal structure of the 3-palladaindan-1-one, [Pd{C6H[C(O)CH2]-6-(OMe)3-2,3,4}(Me2NCH2CH2NMe2)]

Reactions of [Pd(RH)Cl(L–L)][RH= C6H(CHO)-6-(OMe)3-2,3,4] with Ph3PCHR (R = Ph or 2-pyridyl) gave mixtures of the isomeric compounds [Pd(E-R′)Cl(L–L)] and [Pd(Z-R′)Cl(L–L)][R′= C6H(CHCHPh)-6-(OMe)3-2,3,4 or C6H{CHCH(C5H5N-2)}-6-(OMe)3-2,3,4] when L–L = 2,2′-bipyridine or only the corresponding E isomers when L–L =N,N,N′,N′-tetramethylethylenediamine; however, the complex [Pd(RME)Cl(tmeda)][RME= C6H{C(O)Me}-6-(OMe)3-2,3,4] reacts with Ph3PCHPh to give [[graphic omitted]]-6-(OMe)3-2,3,4}(tmeda)].

Room-temperature oxidation of 2-aminobenzoyl- to2-aminobenzoato-palladium(ii) complexes and of coordinated PPh3by atmospheric oxygen; X-ray crystal structure of[(PPh3)2Pd(NH2C6H4CO2-2)Pd{C(O)C6H4NH2-2}(PPh3)]O3SCF3

trans-[Pd(C 6 H 4 NH 2 -2)I(PPh 3 ) 2 ] reacts with CO to give the insertion product trans-[Pd{C(O)(C 6 H 4 NH 2 -2) }(PPh 3 ) 2 ]O 3 SCF 3 or, in the presence of atmospheric oxygen, [(PPh 3 ) 2 - Pd(NH 2 C 6 H 4 CO 2 -2)Pd{C(O)C 6 H 4 NH 2 -2}(PPh 3 )]O 3 SCF 3 , whose crystal structure is solved.