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ACE-INHIBITORS THROUGH THE REACTION OF 4-HYDROXY-2-BUTYNOATES WITH (S)-AMINO-ACID ESTERS - A STRUCTURAL STUDY ON N-[3-(4'-DIMETHYLAMINOPHENYL)-1-(S)-ETHOXYCARBONYL-3-OXOPROP-1-YL]-(S)-ALANINE BENZYL ESTER
No full textThe crystal and molecular structure of the title compound has been determined by single crystal X-ray diffraction data collected using both Mo-K-alpha and Cu-K-alpha radiations. The results of the two analyses are in good agreement and confirm the NMR-based regiochemistry of the conjugate addition step. The molecule has an extended conformation and the two asymmetry centres have the same SS chirality. The conformation is discussed on the basis of the van der Waals-interaction
Configuration and Conformation of (3S,3aR,4R,7S,7aS)-3-Carboxy-4-methyl-7-methylethyl-3a,4,5,6,7,7a-hexahydro-2(3H)-benzofuranone
No full textAlumina/Chloroform-promoted conversion of the ruthenacycles [Ru(CH2CMe2CH2)(eta-6-C6Me6)(PRPh2)] (R = Me or Ph) into the Chloro orthometallated derivatives [Ru(C6H4PRPh)Cl(eta-6-C6Me6)]
No full textInteraction of the ruthenacyclobutanes [Ru(CH2CMe2CH2)(eta6-C6Me6)(PRPh2)] (R = Me 1 or Ph 3) with neutral alumina causes the decomposition of the metallacyclic moiety, with the formation of 1,1-dimethylcyclopropane, neopentane and alumina-adsorbed metal complexes which lead to the corresponding chloro orthometallated compounds [Ru(C6H4PRPh)CI(eta6-C6Me6)] (R - Me 2 or Ph 4) by reaction with CHCl3. The X-ray crystal structure of complex 2 reveals the presence of clathrated benzene. Crystal data: space group P2(1)/c, a = 14.068(14), b = 15.392(13), c = 13.064(14) angstrom, beta = 116.38(6)-degrees, Z = 4, R = 0.0510
Sulphonation of Palladium-Carbon Bonds: Synthesis and X-Ray Crystal Structures of the Disulphinato Derivatives [Pd{S(O)2CH2CH2CH2CH2S(O)2}(tmen)](tmen=Me2NCH2CH2NMe2) and [Pd{S(O)2Me}2(tmen)]
No full textThe sulphonation of [Pd(CH2CH2CH2CH2M)(tmen)] (1a) and [PdMe2(tmen)] (1b) (tmen = Me2NCH2CH2NMe2) in CH2Cl2 leads to the corresponding disulphinato compounds [Pd{S(O)2CH2CH2CH2CH 2S](O)2}(tmen)] (2a) and [Pd{S(O)2Me}2(tmen)] (2b), while the reaction of (1a) and (1b) with liquid SO2 gives the derivatives [Pd{S(O)2CH2CH2CH2CH 2S(O)2}(tmen)]·2SO2 (3a) and [Pd{S(O)2Me}2(tmen)]·2SO2 (3b) respectively. On heating under vacuum, (3a), and (3b) lose SO2 and revert to the disulphinates (2a) and (2b), respectively, which give (3a) and (3b) on reaction with liquid SO2. The X-ray crystal structures of complexes (2a) and (2b) have been determined: (2a), a = 9.259(8), b = 13.380(10), c = 6.213(5) Å, β = 92.96(2)°, space group P21, Z = 2, R = 0.0325 for 2 619 observed reflections; (2b), a = 9.377(2), c = 16.182(3) Å, space group P41212, Z = 4, R = 0.0396 for 1 249 observed reflections. The absolute configurations of the two structures have been determined, and the conformations of the two molecules compared. The metal co-ordination in both compounds is square planar with a very small tetrahedral deformation: av. Pd-S 2.288(1) and av. Pd-N 2.168(4) Å. Closure of the Pds(CH2)4S chelate ring in compound (2a) causes a small increase in the S-Pd-S angle which is 91.3(1)° in (2a) and 90.3(1)° in (2b), but does not significantly influence the co-ordination of the diamine [av. N-Pd-N 82.9(1)°]. The conformation of the palladadithiaheptane ring in (2a) is twisted-boat
Synthesis, X-Ray Structure, and Reactivity with Lewis Acids of Metallacyclopentane Derivatives of Rhodium(III) and Iridium(III). Observation of the First Boron Trifluoride-promoted C-H Bond Activation in Transition Metal Alkyls
No full textThe metallacyclopentanes [M{CH 2CH(R)CH(R′)CH 2}(η 5-C 5Me 5)(PPh 3)] [(1b) M = Rh, R = Me, R′ = H; (1c) M = Rh, R = R′ = Me; (1e) M = Ir, R = Me, R′ = H; (1f) M = Ir, R = R′ = Me; (1g) M = Ir, R = Pr i, R′ = H] were prepared by reacting the appropriate alkylating reagent M′[CH 2CH(R)CH(R′)CH 2]M′ (M′ = Li or MgCl) with the dichlorides of formula [MCl 2(η 5-C 5Me 5)(PPh 3)]. Complexes (1) were characterized by elemental analysis, 1H n.m.r., and mass spectrometry. The X-ray crystal structures of (1c), (1e), and (1f) have been determined. (1c) and (1f) give isostructural P2 1/c crystals, while (1e) crystallizes in the space group C2/c. The cell constants are: (1c), a = 14.982(9), b = 11.058(6), c = 18.421(10) Å, β = 101.13(2)°, Z = 4, R (3 964 reflections, 493 parameters) = 0.0443; (1e), a = 33.63(4), b = 9.29(1), c = 20.56(2) Å, β = 116.6(2)°, Z = 8, R (3 196, 476) = 0.0472; (1f), a = 15.01(2), b = 11.10(1), c = 18.44(2) Å, β = 100.90(4)°, Z = 4, R (4 136, 446) = 0.0334. All compounds possess a structure of the 'three-legged piano stool' type, the major differences lying in the puckering of the metallacyclopentane rings which is larger in the dimethylated derivatives (1c) and (1f) than it is in (1e), where the metallacyclic moiety is rather flattened. The endocyclic C β-C β′, bond in (1e) is 1.34(3) Å, while it is 1.51(1) and 1.52(1) Å in (1c) and (1f), respectively. The rhoda- and irida-cyclopentanes (1a) (M = Rh, R = R′ = H), (1b), (1c), (1d) (M = Ir, R = R′ = H), (1e), and (1f) react under very mild conditions, with BF 3·Bu n 2O and with [CPh 3][PF 6] to give the η 3-allyl complexes [M{η 3-CH 2C(R)C(R′)Me}(η 5-C 5Me 5)(PPh 3)][BF 4] (2) and [M{η 3-CH 2C(R)C(R′)Me}(η 5-C 5Me 5)(PPh 3)][PF 6] (3) [(a) M = Rh, R = R′ = H; (b) M = Rh, R = Me, R′ = H; (c) M = Rh, R = R′ = Me; (d) M = Ir, R = R′ = H; (e) M = Ir, R = Me, R′ = H; (f) M = Ir, R = R′ = Me], respectively, via the regiospecific hydrogen abstraction from the alkyl-substituted β-carbon atom by Lewis acids. Complexes (2) and (3) were characterized by elemental analysis, 1H n.m.r., and fast atom bombardment mass spectrometry
Cyclometallation Reactions in Neopentyl and Trimethylsilyl methyl Systems of Rhodium(III) and Iridium(III). Formation and X-Ray Crystal Structures of the Four-membered Metallacycles [Rh(CH2CMe2CH2)(eta-5-C5Me5)(PPh3)] and [Ir(CH2SiMe2CH2)(eta-5-C5Me5) (PPh3)]
No full textfull title:Cyclometallation reactions in neopentyl and trimethylsilylmethyl systems of rhodium(III) and iridium(III). Formation and X-ray crystal structures of the four-membered metallacycles [Rh(CH2CMe2CH2)(η5-C 5Me5)(PPh3)] and [Ir(CH2SiMe2CH2)(η5-C 5Me5)(PPh3)] The interaction of [RhCl2(η5-C5Me5) (PPh3)] with Mg(CH2CMe3)Cl in pentane gives the rhodacyclo butane [Rh(CH2)(η5-C5Me5)(PPh 3)] (2). The analogous reaction of [MCl2(η5-C5Me5)(PPh 3)] (M = Rh or Ir) with Mg(CH2SiMe3)Cl allows the isolation of the dialkyl derivatives [M(CH2SiMe3)2(η5-C 5Me5)(PPh3)]. Thermolysis of [Ir(CH2SiMe3)2(η5-C 5Me5)(PPh3)] in cyclohexane leads to the iridasilacyclobutane derivative [Ir(CH2SiMe3CH2) (η5-C5Me5) (PPh3)] (6). The mechanism of formation of the metallacyclobutane derivatives is discussed. The X-ray crystal structures of (2) and (6) have been determined. The two metallacycle compounds give isostructural crystals belonging to the P21/n space group with four molecules in the unit cell of dimensions for (2): a = 17.199(6), b = 10.987(4), c = 16.064(5) Å,β = 109.54(2)°; (6): a = 17.098(7), b = 11.294(5), c = 15.977(7) Å,β = 108.17(2)°. Their crystal structures, refined to R = 0.0441 and 0.0389 for (2) and (6) respectively, are built up of deformed 'three-legged piano stools', one leg being the M-P bond [Rh-P = 2.230(2), Ir-P = 2.236(2) Å], the other two being the M-C a bonds [Rh-C = 2.1 00(5) (av.), Ir-C = 2.1 59(7) Å (av.)] of the metallacyclobutane ring with C-Rh-C = 66.8(2) and C-Ir-C = 77.3(4)°. These rings are puckered: angle between M-C ⋯ C and E-C ⋯ C = 16.5(4) and 18.9(6)° for (2) (E = C) and (6) (E = Si), respectively
Neopentyl and Trimethylsilylmethyl Compounds of Rhodium(III) and Iridium(III) with ortho-Metallated Triphenylphosphine. X-Ray Crystal Structure of [Ir(C6H4PPh2)(CH2SiMe3)(eta-5-C5Me5)]
No full textThe compound [RhCl2(η5-C5Me5) (PPh3)] reacts with Li(CH2SiMe3) to give the ortho-metallated complex [R[graphic omitted]Ph2)(CH2SiMe3)(η5-C 5Me5)] (2), and with Mg(CH2SiMe3)Cl in CH2Cl2 (molar ratio 1:1) to yield [RhCl(CH2SiMe3) (η5-C5Me5) (PPh3)], (3). Complex (3) is converted by the action of Li(CH2SiMe3) into the ortho-metallated compound (2). The reaction of [IrCl2(η5-C5Me5)-(PPh 3)] with Mg(CH2SiMe3)Cl in CH2Cl2 gives [I[graphic omitted]Ph2)(CH2SiMe3)(η5-C 5Me5)], (6), and [lrCl(Me)(η5-C5Me5)(PPh3)]. Reaction of [RhCl2(η5-C5Me5)(PPh 3)] with Mg(CH2CMe3)Cl or Li(CH2CMe3) in diethyl ether affords a mixture of [R[graphic omitted]H2)(η5 -C5Me5)(PPh3)], [R[graphic omitted]Ph2)(CH2CMe3)(η5-C 5Me5)], and [Rh(η5-C5Me5)(C2H 4)(PPh3)], while reaction in CH2Cl2 in equimolar amounts gives [RhCl(CH2CMe3)(η5-C5Me 5)(PPh3)]. Reaction of [lrCl2(η5-C5Me5) (PPh3)] with Mg(CH2CMe3)Cl gives [I[graphic omitted]Ph2)(CH2CMe3)(η5 -C5Me5)]. The X-ray crystal structure analysis of compound (6) has been carried out: a = 17.537(7), b = 11.304(4), c = 15.410(7) Å, β = 94.49(1)°, space group P21/n, Z = 4, R = 0.0361 for 4114 observed reflections. The 'piano-stool' metal co-ordination polyhedron is deformed by ortho-metallation which imposes a 67.0(2)° angle at iridium in the metallacycle, while the other angles, P-Ir-C(17) 89.0(2) and C(17)-Ir-C(36) 89.2(2)°, between the 'legs' of the 'stool' are near to 90°. The bulky C5Me5 ligand (effective cone angle 146°), in approaching the metal, produces large widenings of the other co-ordination polyhedron angles: Cp-Ir-P 137.0(3), Cp-Ir-C(36) (benzene)133.4(3)°, and Cp-Ir-C(17) (silyl)122.6(3)° (Cp = centroid of C5Me5). The ortho-metallated ring is nearly planar, (P-Ir-C) ∧ (P-C-C) 5.3(3)°, and bent by only 6.6(2)° with respect to the metal-bound benzene ring which maintains its planarity; the only deformation this ring suffers involves the endocyclic angles at the carbon bound to phosphorus which widen to 124.5(5)° and at the ortho carbons which narrow to 115.9(6) and 116.7(5)°
eta-6-Arene-stabilized Ruthenacyclopentanes: Syntesis, X-Ray Structures, and Reaction with the Trityl Cation
No full textThe ruthenacyclopentane complexes [Ru(CH2CH2CH2CH2)(η 6-C6Me6)L][L = PPh3 (2a), PMePh2 (2b), or PMe2Ph(2c)] have been prepared by reacting the corresponding dichlororuthenium derivatives with an excess of 1,4-dilithiobutane. Their crystal structures have been determined: (2a) and (2b) have space group P21/n crystals, while (2c) crystallizes in space group P21/c. Cell constants: (2a), a = 9.249(3), b = 16.160(7), c = 19.094(21) Å, β = 90.70(1)°, Z = 4, and R (3 203 reflections, 453 parameters) = 0.0425; (2b), a = 17.463(13), b = 8.708(6), c = 17.749(13) Å, β = 109.15(4)°, Z = 4, and R (3 412, 436) = 0.0395; (2c), a = 9.575(6), b = 11.899(8), c = 19.494(12) Å, β = 97.96(2)°, Z = 4, and R (3 080, 383) = 0.0330. All compounds possess structures of the 'three-legged piano stool' type, and the metallacyclopentane ring is puckered having a twisted conformation which is intermediate between the envelope and half-chair forms. The orientations of the hexamethylbenzene and phosphine ligands are considered with respect to the minima of the van der Waals conformation energies of the free molecules. The ruthenacyclopentanes-(2a)-(2c) react at room temperature with [CPh3] [BF4] to give the η3-allylic complexes [Ru(η3-CH2CHCHMe) (η6-C6Me6)L][BF4][L = PPh3 (3a), PMePh2 (3b), or PMe2Ph (3c)]
Synthesis and Thermal Decomposition of Palladacyclopentane Derivatives of the type [Pd(CH2CHRCHRCH2)L2] (R=H or Me). X-Ray Crystal Structure of [Pd(CH2CH2CH2CH2)(bipy)]
No full textA series of new palladacyclopentane derivatives of formula [Pd(CH2)CHRCHRCH2L2] [L2 = (C6H11)2PCH2CH2P(C 6H11)2 (dcpe) or Ph2P(CH2)4PPh2 (dppb), R = H; L2 = Ph2PCH2CH2PPh2 (dppe), 2,2′-bipyridyl (bipy), or Me2NCH2CH2NMe2 (tmen), R = Me] has been prepared. The first X-ray crystal structure determination of a palladacyclopentane derivative is reported: the compound [Pd(CH2CH2CH2CH2)(bipy)] gives crystals belonging to the C2/c space group: a = 16.643(9), b = 11.174(4), c = 7.451(3) Å, β = 116.05(9)°, and Z = 4; R = 0.0340 for 826 observed reflections. The metal co-ordination is square planar and the molecules lie on a two-fold axis. The palladacyclopentane ring shows a half-chair conformation with the two-fold axis running through Pd and the middle of the C(β)-C(β′) bond. A study of the thermal decomposition of the palladacyclopentanes has been carried out: [Pd(CH2CH2CH2CH2)L2] (L = PPh3; L2 = dppe, tmen, bipy, dcpe, or dppb) gives butenes as the major products; cyclobutane (L = PPh3) and ethylene (L2 = dppe or dcpe) are also formed as minor products. By comparing these results with those for the decomposition of some methyl-substituted palladacyclopentanes, it is shown that the presence of ethylene is not attributable to fragmentation of the metallacyclic skeleton, but rather to the rupture of the P-C bonds of the diphosphine ligands. The decomposition of palladacyclopentanes is also induced by Bun 2O·BF3: linear C4 hydrocarbons are formed
Cyclometallation of Phenyl Phosphine and Neopentyl Ligands in Ruthenium(II) Complexes: Synthesis and Crystal Structure of the Orthometallated Complexes [Ru(C6H4PR1R2)(CH2CMe3)(eta-6-C6Me6)] (R1 = R2 = Ph; R1 = Me, R2 = Ph; R1 =R2 = Me) and of the Metalla-cyclobutanes [Ru(CH2CMe2CH2)(eta-6-C6Me6)(PPhR1R2)] (R1 = R2 = Ph; R1 = Me, R2 = Ph)
No full textThe compounds [RuCl2(eta-6-C6Me6)L] (L = PPh3 1, or PMePh2 2) react with an excess of Mg(CH2CMe3)Cl to give the corresponding orthometallated complexes activated [Ru(C6H4PR1R2)(CH2CMe3)-(eta-6-C6Me6)] [R1 = R2 = Ph, 4; R1 = Me, R2 = Ph, 5, only the diastereomer (RS:SR)], and the metallacyclobutanes activated [Ru(CH2CMe2CH2)(eta-6-C6Me6) (PPhR1R2)] (R1 = R2 = Ph, 7; R1 = Me, R2 = Ph, 8). In contrast [(RuCl2(eta-6-C6Me6)(PMe2Ph)] 3 reacts to give only the orthometallated complex activated [Ru(C6H4PMe2)(CH2CMe3)(eta-6-C6Me6)] 6. The X-ray crystal structures of complexes 4-8 have been determined and their conformations are discussed. Crystal data are: 4, a = 10.483(2), b = 16.050(10), c = 18.451(9) angstrom, beta = 103.65(4)-degrees, Z = 4, space group P2(1)/c, R = 0.0548; 5, a = 11.926(3), b = 17.810(5), c = 12.780(3) angstrom, beta = 99.37(1)-degrees, Z = 4, space group P2(1)/c, R = 0.0480; 6, a = 16.762(21), b = 10.116(10), c = 14.874(15) angstrom, beta = 108.08(5)-degrees, Z = 4, space group P2(1)/n, R = 0.0441; 7, a = 10.720(20), b = 11.670(20), c = 12.050(10) angstrom, alpha = 80.32(4), beta = 78.60(10), gamma = 87.88(3)-degrees, Z = 2, space group P1BAR, R = 0.0232; 8, a = 8.842(10), b = 8.898(20), c = 17.840(70) angstrom, alpha = 92.91(6), beta = 102.48(50), 102.48(50), gamma = 103.12(9)-degrees, Z = 2, space group P1BAR, and R = 0.0529
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