Synthesis,stereochemistry, and spectroscopic characterization of [Rh(η4-cod){(R)-2-(X-benzaldimine)-2-phenylethanol-κ 2 N,O}](acetate) (X = H; 2,4-dimethoxy)

Condensation of X-benzaldehyde with (R)-2-amino-2-phenylethanol gives the enantiopure Schiff bases (R)-2-(X-benzaldimine)-2-phenylethanol (X?=?H, HL1; 2,4-dimethoxy, HL2). The Schiff bases coordinate with dinuclear [Rh(η⁴-cod)(µ-O₂CCH₃)]₂ to afford the cationic complexes [Rh(η⁴-cod){(R)-2-(benzaldimine)-2-phenylethanol-κ ² N,O}](acetate), [Rh(η⁴-cod)(HL1)](ac) (1) and [Rh(η⁴-cod){(R)-2-(2,4-dimethoxy-benzaldimine)-2-phenylethanol-κ ² N,O}](acetate), [Rh(η⁴-cod)(HL2)](ac) (2), respectively. The Schiff bases and complexes are isolated as solids in good yields and characterized by elemental analysis, IR, UV-Vis, ¹H/¹³C-NMR, mass spectroscopy, and polarimetry.     

Syntheses and Structures of the Hexacoordinated Antimony Complexes: Ph3(C2H4O2)Sb⋅⋅⋅DMSO, (3-FC6H4)3(C2H4O2)Sb⋅⋅⋅DMSO,and (4-MeC6H4)3(C6H4O2)Sb⋅⋅⋅DMSO

Russian Journal of Coordination Chemistry - Complexes Ph3(C2H4O2)Sb???DMSO (I), (3-FC6H4)3(C2H4O2)Sb???DMSO (II), and...     

Synthesis and Structure of Tetraphenylantimony Oximates Ph4SbON=CRR′ (CRR′ = C6H9−C6H9-2 and R = Ph,R′ = C(O)Ph)

The reaction of pentaphenylantimony and the oxime HON=CRR taken in 1 : 1 molar ratio in toluene gave tetraphenylantimony oximates Ph₄SbON=CRR (CRR = C₆H₉–C₆H₉-2 (I) and R = Ph, R = C(O)Ph (II)). According to X-ray diffraction data, the Sb atoms in I and II have a distorted trigonal-bipyramidal coordination with oximate ligands in the axial positions. The C_axSbO angles are 177.6(1)° in I and 176.58(6)° in II. The Sb–C bond lengths lie in the ranges of 2.120(4)–2.203(4) Å for I and 2.122(2)–2.181(2) Å for II. The Sb–O bond lengths are 2.120(2) Å (I) and 2.166(1) Å (II). The lengths of the intramolecular Sb···N contacts are 2.806(3) and 2.918(2) Å in I and II, respectively.     

The synthesis,electrochemistry and molecular structure of [Fe(η5-C5H4S)2Mo(NO){HB(3,5-Me2C3N2H)3}]

The new bimetallic complex [Fe(η⁵-C₅H₄S)₂Mo(NO){HB(3,5-Me₂C₃N₂H)₃)}] has been obtained from the reaction between [Fe(η⁵-C₅H₄SH)₂] and [Mo(NO){HB(3,5-Me₂C₃N₂H)₃}I₂]. Electrochemical studies reveal an anomalously cathodic oxidation potential for the metallocene redox centre. An X-ray diffraction study has revealed an FMo distance of 4.147(2) Å, with the ferrocenyl moiety oriented towards the nitrosyl ligand on the molybdenum atoms (Fe---O 3.976(6) Å), but provides no evidence for an interaction between the iron atom and the molybdenum-bound nitrosyl which might account for the electrochemical findings.     

Reactions of Triruthenium Clusters with Quinolines: X-Ray Structures of [Ru3(μ-CO)(CO)7{μ3-η2-P(C6H5)CH2P(C6H5)2)}{μ-η2-C9H5(CH3)N}] and [Ru3(CO)10(μ-H){μ-η2-C9H6N}]

The reactions of [Ru₃(CO)₁₀(μ-dppm)] 4 with quinolines afforded [Ru₃ (μ-CO)(CO)₇{μ₃-η²-P(C₆H₅)CH₂P(C₆H₅)₂)}{μ-η²-C₉H₅(R)N}] (8, R = 4-Me; 9, R = H) as the major products along with small amounts of known compound [Ru₃(CO)₉{μ₃-η³-P(C₆H₅)CH₂P(C₆H₅)(C₆H₄)}] 5. The molecular structure of 8 has been determined by single crystal X-ray studies. The reaction of 5 with 4-methylquinoline in refluxing cyclohexane afforded 8 and two known dinuclear compounds, [Ru₂(CO)₆{μ-CH₂P(C₆H₅)(C₆H₄)P(C₆H₅}] 10 and [Ru₂(CO)₆ {μ-(C₆H₄)P(C₆H₅)(CH₂)P(C₆H₅}] 11, in 40, 12, and 10% yields, respectively. The compounds 10 and 11 are also formed from the thermolysis of 4 in addition to the major compound 5. The solid state structure of the previously reported [Ru₃(CO)₁₀(η-H){μ-η²-C₉H₆N}] 2a is also reported for comparison.     

Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

The behavior of different anilines H₂NC₆H₄R (R = o-Me, p-Me, o-, m- and p? ⁱ Pr, p-OMe, p-CO₂Et) and 2,6-Me₂C₆H₃NH₂ towards trihalophosphoranes was studied. 2,6-Me₂C₆H₃NH₂ failed to form the diaminophosphonium salt [Ph₂PNH(2,6-Me₂C₆H₃)₂]Br, and the aminophosphine oxide Ph₂(2,6-Me₂C₆H₃NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.     

Syntheses,structures, and properties of transition metal complexes with 2-( n -pyridyl)benzimidazole ( n = 2, 3, and 4)

Three pyridylbenzimidazoles (2-PBIM, 3-PBIM, and 4-PBIM) have been prepared (2-PBIM: 2-(2-pyridyl)-benzimidazole, 3-PBIM: 2-(3-pyridyl)-benzimidazole, 4-PBIM: 2-(4-pyridyl)-benzimidazole). Reactions of several transition metals (Cd²⁺, Cu²⁺, Fe²⁺) with the three ligands gave four new coordination complexes, [(Cd)₂(2-PBIM)₂(CH₃COO)₄] (1), [Cu(3-PBIM)₂(CH₃COO)₂]?·?2H₂O (2), [Cu(4-PBIM)₂(CH₃COO)₂(H₂O)]?·?H₂O (3), and [Fe(4-PBIM)₂(Cl)₂(H₂O)₂] (4), respectively. These four complexes have been characterized by X-ray crystallography, IR spectroscopy, and UV absorption spectroscopy. Thermogravimetric properties of 2 and 4 were also measured. X-ray crystallographic studies reveal that these four complexes are very different, although the ligands are similar in structure. The role of hydrogen-bonding and π–π interactions in extending dimensionality of simple complexes has been discussed.     

Synthesis and structures of complexes Os3(μ-H)2(CO)7(μ-RC5H3N){μ3-Ph2PCH2P(C6H4)Ph} (R = H, Me) with ortho-metalated pyridine ligands. The revised structure of the triosmium cluster ”Os3(μ-H)2(CO)7(μ-C6H4){μ3-Ph2PCH2P(C6H4)Ph}”

The structure of the previously synthesized triosmium cluster was revised. The structure Os₃(μ-H)₂(CO)₇(μ-C₆H₄){μ₃-Ph₂PCH₂P(C₆H₄)Ph} suggested earlier was not confirmed. The cluster has the composition Os₃(μ-H)₂(CO)₇(μ-C₅H₄N){μ₃-Ph₂PCH₂P(C₆H₄)Ph} and contains the ortho-metalated pyridine ligand. The X-ray diffraction study of the complex Os₃(μ-H)₂(CO)₇(μ-MeC₅H₃N){μ₃-Ph₂PCH₂P(C₆H₄)Ph} containing the ortho-metalated 4-methylpyridine ligand made it possible to distinguish between the C and N atoms of the pyridine ligands in the resulting triosmium clusters.     

Unexpected Carbon–Carbon Bond Cleavage in the Reactions of the Pentagonal Bipyramidal Cluster Fe3(CO)6(μ-CO)2[μ3-η4-{RCC(Et)C(Et)CR}] with Styrene. Synthesis and X-ray Structure of Fe3(CO)6[μ3-η4-{EtC2CR}]2 (R = CH3(=CH2))

The thermal reactions of 2-methyl-1-hexen-3-yne [CH₃CH₂C≡CC(=CH₂)CH₃, metey] with Fe₃(CO)₁₂ have been studied: cluster opening or fragmentation and alkyne dimerization occur. Main products are the open triangular isomers [Fe₃(CO)₆(μ-CO)₂{CH₃(=CH₂)CC(Et)C(Et)C(=CH₂)CH₃}] (complex 3a) and [Fe₃(CO)₆(μ-CO)₂{C(Et)CCH₃(=CH₂)C(Et)CCH₃(=CH₂)}] (complex 3b). The structure and isomerism of the complexes has been confirmed by X-ray studies. The minor products of the reaction have been characterized by spectroscopic techniques. An attempt at exploiting the reactivity of the “free” C=C bonds of the coordinated ene-yne was made: complex 3a was reacted with styrene under thermal conditions. Unexpectedly considerable yields of the closed triangular cluster [Fe₃(CO)₆{EtC₂C(=CH₂)CH₃}₂] (complex 5) have been obtained. This behaviour had not been previously observed. The unprecedented structure of complex 5 has been confirmed with an X-ray study.     

Synthesis and Crystal Structure of [ Cp* Ru(η6- C6H5B Ph3)]

The title complex [Cp*Ru(η6-C6H5BPh3)] has been synthesized by the reaction of [Cp*Ru(H2O)(NBD)]BF4 with H2 and NaBPh4, and its crystal structure was determined by singlecrystal X-ray diffraction analysis. It crystallizes in triclinic, space group P(1) with a = 11.0610(10), b = 11.2317(10), c = 12.3633(11) (A), α = 81.419(2), β = 67.8370(10), γ = 88.370(2)°, V= 1405.9(2) (A)3,Z= 2, C34H35BRu, Mr= 555.50, Dc = 1.312 g/cm3, F(000) = 576 and μ(MoKa) = 0.577 mm-1. The final R and wR are 0.0559 and 0.1483, respectively for 4365 observed reflections with I ＞ 2σ(Ⅰ). In the title complex, the four phenyl rings bonded to the B atom are deposited in a tetrahedral geometry,and one of the phenyl rings is η6-bonded to ruthenium.     

Syntheses,spectroscopy, and catalysis of (η 4-cod)Rh(I)-complexes with (R or S)-2-(salicylaldimine)-2-phenylethanol or (rac)-2-(salicylaldimine)-1-phenylethanol

Condensation of salicyldehyde with (R or S)-2-amino-2-phenylethanol or rac-2-amino-1-phenylethanol gives enantiopure (R or S)-2-(salicylaldimine)-2-phenylethanol (R- or S-H₂L1) or (rac)-2-(salicylaldimine)-1-phenylethanol (rac-H₂L2). The Schiff bases coordinate to [Rh(η ⁴-cod)(μ-O₂CCH₃)]₂ to afford mononuclear [Rh(η ⁴-cod){(R or S)-2-(salicylaldiminato)-2-phenylethanol-κ ² N,O}], [Rh(η ⁴-cod)(R- or S-HL1)] (1 or 2), or [Rh(η ⁴-cod){(rac)-2-(salicylaldiminato)-1-phenylethanol-κ ² N,O}], [Rh(η ⁴-cod)(rac-HL2)] (3). The Schiff base and complexes are characterized by IR-, UV/Vis-, ¹H/¹³C-NMR-, mass-spectroscopy, circular dichroism (CD), and polarimetry. The synthetic and spectroscopic results suggest that deprotonated Schiff base coordinates to [Rh(η ⁴-cod)] as a six-membered N,O-chelate with distorted square planar geometry at rhodium. CD and polarimetry measurements show the enantiopurity of the Schiff bases as well as the complexes in solution. The in situ system composed of [Rh(η ⁴-cod)Cl]₂ and S-H₂L1 has been used as a catalyst for the reduction of acetophenone into rac-1-phenylethanol with 85% conversion in diphenylsilane at 0–5°C.     

Novel Hydrogen Transfer Reactions to the Ligated 1,2,4-Triphosphole in [Ru(η4-C8H12){η-P3C2But 2CH(SiMe3)2}]

INTRODUCTION

As discussed in a recent preliminary publication¹, the complex [Ru(η⁴-C₈H₁₂){η-P₃C₂Bu^t ₂CH(SiMe₃)₂}] (1) (C₈H₁₂ = cycloocta-l,5-diene) was prepared by the reaction of [Ru(η⁶-C₁₀H₈)(η⁴-C₈H₁₂)] (2) (C₁₀H₈ = naphthalene) with the 1,2,4-triphosphole P₃C₂Bu^t ₂CH(SiMe₃)₂ (3) (Fig. 1), illustrating the aromatic behaviour of (3).     

β-Lactam Ring Opening in the Reformatsky Reaction of (3R,4R)-4-Acetoxy-3-((1R)-1-{[tert-butyl(dimethyl)silyl]oxy}ethyl)azetidin-2-one with Ethyl 4-Bromo-3-oxopentanoate

Russian Journal of Organic Chemistry - The Reformatsky reaction of (3R,4R)-4-acetoxy-3-((1R)-1-{[tert-butyl(dimethyl)silyl]oxy}ethyl)­azetidin-2-one with ethyl 4-bromo-3-oxopentanoate gave...     

Synthesis of dibenzocymantrene derivatives (η5-9-RC13H8)Mn(CO)3 (R = Ph and But). Crystal structure of (η5-9-PhC13H8)Mn(CO)3

⁵-Fluorenyl complexes of manganese (⁵-9-RC₁₃H₈)Mn(CO)₃, where R = Ph (1) and But (2), have been prepared and characterized for the first time. The structure of complex1 has been established by X-ray structural analysis.Yu T. Yanovsky deceased in 1995.Translated fromIZvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 199–203, January, 1996.     

Enantiogenic synthesis of (R)-(−)-3-hydroxy-1-penten-4-one

Condensation of pyruvate and acrolein with whole cells of baker's yeast resulted in a mixture of 3-hydroxy-1-penten-4-one 1 and 4-hydroxy-1-penten-3-one 2. The absolute configuration (R) and the enantiomeric excess (ee 72%) of the compound 1 were determined.     

Syntheses of (η6-p-cymene)ruthenium(II) piano-stool amine complexes: molecular structure of [(η6-C10H14)RuCl2(H2N-C6H4-p-Cl)]

The dimeric complex [{(η⁶-p-cymene)Ru(μ-Cl)Cl}₂] (1) reacts with S,N-donor Schiff base ligands, para-substituted S-(thiophen-2-ylmethylene)phenylamines in methanol to give mononuclear amine complexes of the type [(η⁶-p-cymene)RuCl₂(NH₂–C₆H₄–p-X)] {X?=?H (2a); X?=?CH₃ (2b); X?=?OCH₃ (2c); X?=?Cl (2d); Br (2e) X?=?NO₂ (2f), respectively} by hydrolysis of the imine group of the ligand after coordination to the metal. The complexes were characterized by analysis and IR and NMR spectroscopy. The molecular structure of [(η⁶-C₁₀H₁₄)RuCl₂(H₂N–C₆H₄–p-Cl)] (2d) was established by a single-crystal X-ray diffraction study.     

Chalcogen–acetylide interaction and unusual reactivity of coordinated acetylide with water: synthesis and characterisation of [(η5-C5R5)Fe3(CO)6(μ3-E)(μ3-ECCH2RI)] (R=H,Me; RI=Ph,Fc; E=S,Se) and [(η5-C5R5)MoFe2(CO)6(μ3-S)(μ-SCCH2Ph)] (R=H,Me)

Photolysis of a benzene solution containing [Fe₃(CO)₉(μ₃-E)₂] (E=S, Se), [(η⁵-C₅R₅)Fe(CO)₂(CCR^I)] (R=H, Me; R^I=Ph, Fc), H₂O and Et₃N results in formation of new metal clusters [(η⁵-C₅R₅)Fe₃(CO)₆(μ₃-E)(μ₃-ECCH₂R^I)] (R=H, R^I=Ph, E=S 1 or Se 2; R=Me, R^I=Ph, E=S 3 or Se 4; R=H, R^I=Fc, E=S 5; R=Me, R^I=Fc, E=S 6 or Se 7). Reaction of [Fe₃(CO)₉(μ₃-S)₂]with [(η⁵-C₅R₅)Mo(CO)₃(CCPh)] (R=H, Me), under same conditions, produces mixed-metal clusters [(η⁵-C₅R₅)MoFe₂(CO)₆(μ₃-S)(μ-SCCH₂Ph)] (R=H 8; R=Me 9). Compounds 1–9 have been characterised by IR and ¹H and ¹³C-NMR spectroscopy. Structures of 1, 5 and 9 have been established crystallographically. A common feature in all these products is the formation of new C-chalcogen bond to give rise to a (ECCH₂R^I) ligand.     

Stereoselective synthesis and absolute configuration of (1′R,3R,4R)-4-acetoxy-3-(2′,2′,2′-trifluoro-1′-hydroxyethyl)azetidin-2-one

The title compound 3, an intermediate in the synthesis of fluorocarbapenems, is obtained with high stereocontrol by the condensation of (R)-(+)-ethyl 4,4,4-trifluoro-3-hydroxybutanoate with N-trimethylsilyl cinnamylidenimine. X-Ray diffraction analysis of the condensation product and chemical correlations allowed the unambiguous determination of the absolute configuration.     

Synthesis of (22R, 25R)-3β,26-Dihydroxy-5α-furostan-6-one #

The synthesis of a plant growth promoter furostanol which bears the characteristic functionality of teasterone on rings A and B is described.