Diastereoselective synthesis and coordination chemistry of enantiopure keto-bis-(2-phosphametallocene)s

Enantiopure 2-(chlorocarbonyl)phosphametallocenes [MCp*(2-{COCl}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) react with phospholide anions to give 2-phosphametallocene-2'-acylphospholides K[MCp*(2-CO-2'-{3',4'-Me(2)-5'-PhPC(4)}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) and these have been converted into keto-bis-(2-phosphametallocene)s through reaction with [FeClCp*(tmeda)]; templation of this process with CuBr gives rise to the C(2)- (or pseudo-C(2)- when M = Ru) symmetric form of [{MCp*(3,4-Me(2)-5-Ph-PC(4))}(2)-2,2'-(CO)] (M = Fe, Ru; Fe, Fe) with high (>95%) diastereoselectivity. X-Ray structures of these ligands coordinated to [RuCp*Cl] and [PtCl(2)] centres show that the spatial orientation of the very flexible keto-bis-(2-phosphametallocene) structure is highly responsive to the coordination sphere of the chelated platinum or ruthenium centre.     

Highly regioselective synthesis of 1-aryl-3 (or 5)-alkyl/aryl-5 (or 3)-(N-cycloamino)pyrazoles

[Reaction: see text]. An efficient highly regioselective protocol for the synthesis of isomeric 1,3-diaryl (or 1-aryl-3-alkyl) and 1,5-diaryl (or 1-aryl-5-alkyl)-5 (or 3)-(N-cycloamino)pyrazoles has been reported by cyclocondensation of common alpha-oxoketene N,S-acetal precursors with arylhydrazines by variation of reaction conditions.     

Diastereoselective synthesis of (R*,R*)-ethyl 2-[1H-indol-3-yl(phenyl)methyl]-3-oxobutanoate

Russian Chemical Bulletin -     

AuCl(3)-catalyzed synthesis of highly substituted furans from 2-(1-alkynyl)-2-alken-1-ones

Highly substituted furans have been synthesized by the reaction of 2-(1-alkynyl)-2-alken-1-ones and various nucleophiles under very mild reaction conditions in good to excellent yields. Gold and some other transition metals are efficient catalysts for this reaction.     

Facile synthesis of 5-(α-alkyl-substituted) furans

2-Halo, 2-hydroxy- or 2-alkoxyalkyl substituted furans are easily synthesized under acidic conditions by intramolecular cyclization of α,β-unsaturated 1,4-diketones by a simple and cheap procedure. Some aspects of the mechanism are discussed.     

Efficient synthesis of new 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrol-2(5H)-ones

The synthesis of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrol-2(5H)-ones 5, 6a-d from 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d is reported. The 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d were obtained from regiospecific bromination of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 1, 2a-d with molecular bromine. The NMR and X-ray diffraction data showed that 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones were brominated at 4-position in the pyrrolidin-2-one ring.     

Crystal Structure and Photochromic Properties of [1-(2-Methyl-5-(4-cyanophenyl)-3-thienyl)]-2-(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene

A new photochromic diarylethene, [1-(2-methyl-5-(4-cyanophenyl)-3-thienyl-2-(2-methyl-5-phenyl-3-thienyl)]perfluorocyclopentene(1o, C28H17F6NS2), was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. Its crystal belongs to the monoclinic system, space group P21/c with a = 24.1381(5), b = 9.3834(6), c = 11.1073(8), β = 94.477(4)°, Z = 4, V = 2508.1(3) A3, D3 c = 1.445 mg/m, μ = 0.275, F(000) = 1112, the final R = 0.0482 and wR = 0.1429 for 5834 observed reflections(I 2σ(I)). Further study demonstrated the diarylethene underwent reversible photochromism, changing between colorless and blue in hexane solution, crystalline phase and PMMA films, respectively.     

2-Amino-3-(benzimidazol-2-yl)benzo[b]furans

The corresponding 2-amino-3-(benzimidazol-2-yl)benzo[b]furans were obtained by reaction of 2,3,5-trimethyl-1,4-benzoquinone with 2-cyanomethylbenzimidazoles. It is shown that new benzo[b]furo[2′,3′∶4,5]pyrimido[1,6-a]benzimidazole polynuclear heterocyclic systems (bases and quaternary salts) are formed in the reaction of these products with acylating agents. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 164–166, February, 1980.     

Synthesis of 2- and 3-alkyl(aryl)-cis-1-thiadecalins

Conclusions For the first time cis- and trans-2- and 3-alkyl-cis-1-thiadecalins were synthesized and some of their physical constants were examined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 393–399, February, 1989.     

Diastereoselective arylation of enantiopure 3-bromopiperidin-2-one derived from (R)-(−)-2-phenylglycinol with organocuprate reagents

The diastereoselective substitution of 3-bromolactam derived from (R)-(−)-2-phenylglycinol with a variety of arylcuprate reagents is presented. The stereochemical outcome of the substitution reaction is discussed. The method provides an efficient and straightforward route to enantiopure 3-arylpiperidines.     

Electronic effect of the 1-[η5-cyclgpentadienyl-η5-(3)-1,2-dicarbollyliron(II)] group

Conclusions The Taft method was used to determine the electronic effect of the 1-[⁵-cyclopenta-dienyl-⁵-(3)-1,2-dicarbollyliron(II) ] group which displays strong electron-donor properties: _I=–0.22 and _R=–0.20.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1449–1451, June, 1985.     

Crystal Structure and Photoreactive Properties of 1-(2,5-Dimethyl-3-thienyl)-2-[2-methyl-5-(N-(quinolin-8-yl)-2-carboxamide)-3-thienyl)]perfluorocyclopentene

The photochromic title compound,C_(26)H_(18)F_6N_2OS_2,contains a 2,5-dimethylthiophene ring and a N-formyl aminoquinolinyl thiophene ring on the C=C double bond of the cyclopentene ring.The dihedral angles between the cyclopentene and attached N-formyl aminoquinolinyl thiophene ring and 2,5-dimethylthiophene ring are 63.0° and 137.1°,respectively.The dihedral angle between the thiophene ring and the adjacent aminoquinoline ring is 5.7°.The molecule adopts an antiparallel conformation,with a distance between the two photoreactive C atoms of 3.763 ?.In addition,the absorption and fluorescence spectral changes were measured in acetonitile and solid at room temperature,and the result showed that the title compound could undergo photochromic reaction in both states.     

Aminomethylation of 2- and 3-(Diethoxyphosphorylmethyl)furans

Dimethyl(methylene)ammonium chloride reacts with 2-, 3-(diethoxyphosphorylmethyl)furansby the free position of the furan ring to give the corresponding aminomethyl derivatives. 2,5-Disubstitutedfurans do not enter this reaction.     

Synthesis of (2-hydroxy-5-nitrophenyl)di[1-(2-hydroxynaphthyl)]methane and 12-[1-(2-hydroxynaphthyl)]-10-nitro-12H-benzo[α]xanthene from of 5-nitrosalicylaldehyde derivatives and β-naphthol

The reaction of the morpholinal or anil of 5-nitrosalicylaldehyde with β-naphthol yielded (2-hydroxy-5-nitrophenyl)di[1-(2-hydroxynaphthyl)]methane. Condensation of the latter compound in boiling nitromethane gave 12-[1-(2-hydroxynaphthyl)]-10-nitro-12H-benzo[α]xanthene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1336–1339, July, 1997.     

Darstellung und Charakterisierung der Pentammin-Komplexe [Os(NH3)5(NCS)]2+ und [Os(NH3)5(NCSe)]2+

Preparation and Characterization of the Pentammine Complexes [Os(NH₃)₅(NCS)]²⁺ and [Os(NH₃)₅(NCSe)]²⁺ The new pentammine complexes [Os(NH₃)₅(NCS)]²⁺ and [Os(NH₃)₅(NCSe)]²⁺ are prepared from the reaction of [Os(NH₃)₅(CF₃SO₃)](CF₃ SO₃)₂ with NH₄SCN and KSeCN, respectively, in acetone, and subsequent purification by ion exchange chromatography on carboxymethyl cellulose. Evidence of N-bonding in both cases is given by the vibrational spectra, indicating that Os³⁺ is in terms of Lewis acidity harder than Ru³⁺, Rh³⁺, and Ir³⁺. I.r. and Raman spectra are interpreted according to local C_4v symmetry around Os, and the presumed assignments are confirmed by comparison with the i.r. spectra of the perdeuterated compounds. In the electronic spectra of both complexes charge transfer bands at 412 nm (NCS) and 498 nm (NCSe) are observed, respectively. Further weak absorptions near 4500 and 5100 cm^?1, which are in correlation with electronic Raman bands, are assigned to intraconfigurational transitions within the ²T_2g (O_h) ground term, split into three Kramers doubletts by spin-orbit coupling and lowered symmetry. Electrochemical measurements demonstrate a stabilisation of +III and +II oxidation states by π-back donation to —NCS and —NCSe ligands.