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Wartchow R, Frackenpohl J, Hoffmann ΗMR. Crystal structure of (1S,2R,4S,5S)-5-ethynyl-2-hydroxymethyl-1-azabicyclo[2.2.2]octane, (HC2)(HOCH2)C7H11N). Z KRIST-NEW CRYST ST 2001. [DOI: 10.1524/ncrs.2001.216.14.245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Kamel LT, Essawi ΜE, Wartchow R, Berthold HJ. Crystal structure of bis[(10,11-dihydro-dibenzo[b,f lazepin-5-yl)-2- methyl-propyl-dimethyl-ammonium] tetrachlorocuprate(II), (C2OH27N2)2[CUCI4]. Z KRIST-NEW CRYST ST 2001. [DOI: 10.1524/ncrs.2001.216.14.381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Clausen C, Wartchow R, Butenschön H. Reactions of 1,2-Diketones with Vinyllithium: Addition Reactions and Dianionic Oxy Cope Rearrangements of Cyclic and Acyclic Substrates. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200101)2001:1<93::aid-ejoc93>3.0.co;2-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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von Ahsen B, Wartchow R, Willner H, Jonas V, Aubke F. Bis(carbonyl)platinum(II) Derivatives: Molecular Structure of cis-Pt(CO)2(SO3F)2, Complete Vibrational Analysis of cis-Pt(CO)2Cl2, and Attempted Synthesis of cis-Pt(CO)2F2. Inorg Chem 2000. [DOI: 10.1021/ic000280j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Braje W, Holzgrefe J, Wartchow R, Hoffmann H. Struktur und Mechanismus in der Cinchonaalkaloid-Chemie: Die wässrige Hydrolyse erfolgt unter vollständiger Inversion der Konfiguration – oder aber vollständiger Retention. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20000616)112:12<2165::aid-ange2165>3.0.co;2-j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Braje WM, Holzgrefe J, Wartchow R, Hoffmann HM. Structure and Mechanism in Cinchona Alkaloid Chemistry: Aqueous Hydrolysis Proceeds with Complete Inversion or Complete Retention of Configuration We thank Stefanie Röper for experimental contributions, Olaf Schrake for discussion, Ulrike Eggert and Lars Ole Haustedt for their help, Dr. Hofer for NMR analysis, and two referees for their critical comments. Our work was supported by the Friedrich-Naumann-Stiftung (PhD. Fellowship for W.M.B.), Chininfabrik Buchler GmbH (gift of Cinchona alkaloids) and the Fonds der Chemischen Industrie. Angew Chem Int Ed Engl 2000; 39:2085-2087. [PMID: 10941022 DOI: 10.1002/1521-3773(20000616)39:12<2085::aid-anie2085>3.0.co;2-n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Röper S, Frackenpohl J, Schrake O, Wartchow R, Hoffmann HM. Synthesis of enantiopure 1-azabicyclo[3.2.2]nonanes via stereoselective capture of chiral carbocations. Org Lett 2000; 2:1661-4. [PMID: 10880195 DOI: 10.1021/ol0057378] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A new class of doubly functionalized and enantiomerically pure 1-azabicyclo[3.2.2]nonanes derived from quincorine and quincoridine is described. 2,5-Disubstituted quinuclidines with a C9-mesyloxy group were easily transformed into the corresponding halides upon treatment with lithium salts. Subsequent silver salt-mediated ring expansion stereoselectively furnished the title azabicyclics. Chiral carbocations which are configurationally stable and nonplanar are postulated to account for the striking stereoselectivity of the capture of external nucleophile. 5-Ethynyl-2-iodomethylquinuclidines afford the alpha-benzoyloxy amines rather than alpha-methoxy amines, even in MeOH.
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Willner H, Bach C, Wartchow R, Wang C, Rettig SJ, Trotter J, Jonas V, Thiel W, Aubke F. Syntheses, molecular structures, and vibrational spectra of chloropentacarbonylrhodium(III) and -iridium(III) undecafluorodiantimonate(V), [Rh(CO)5Cl][Sb2F11]2 and [Ir(CO)5Cl][Sb2F11]2: an experimental and density functional study. Inorg Chem 2000; 39:1933-42. [PMID: 11428113 DOI: 10.1021/ic9911926] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reactions of either bis(mu-chloro)tetracarbonyldirhodium(I), [Rh(CO)2(mu-Cl)]2, or chlorotricarbonyliridium(I), [Ir(CO)3Cl]n, in the conjugate Brønsted-Lewis superacid HF-SbF5 and in a CO atmosphere, produce [Rh(CO)5Cl][Sb2F11]2 or [Ir(CO)5Cl][Sb2F11]2, respectively. In these oxidative carbonylation reactions, antimony(V) fluoride functions as an oxidizing agent. The reduced product is identified as 6SbF3.5SbF5. [Rh(CO)5Cl][Sb2F11]2 is obtained in the form of single crystals. Crystal data: monoclinic, space group P2(1) (No. 4); a = 9.721(1), b = 12.602(1), c = 10.538(1) A; beta = 106.51(1) degrees; V = 1237.7(2) A3; Z = 2; T = 300 K; R1 [I > 3 sigma (I)] = 0.0367, wR2 = 0.0739. Single crystals of [Ir(CO)5Cl][Sb2F11]2 are produced in small amounts from a solution of mer-Ir(CO)3(SO3F)3 in magic acid, HSO3F-SbF5. The possible source of chlorine will be discussed. Crystal data for [Ir-(CO)5Cl][Sb2F11]2: monoclinic, space group P2(1) (No. 4); a = 9.686(2), b = 12.585(2), c = 10.499(2) A; beta = 106.59(2) degrees; V = 1226.5(4) A3; Z = 2; T = 294 K; R1[I > 3 sigma (I)] = 0.032, Rw = 0.031. The bond lengths and bond angles are nearly identical in the two isostructural salts; however, the cell volume of [Ir(CO)5Cl][Sb2F11]2 is slightly smaller than that of [Rh(CO)5Cl][Sb2F11]2. The cations (point group C4v) feature unusually long M-C bonds (M = Rh, Ir) and correspondingly short CO bonds, as well as high CO stretching wavenumbers and high CO stretching force constants. The [Sb2F11]- anions are not symmetry related, and their dihedral and bridge angles differ slightly in both salts. There are significant interionic contacts in [Ir(CO)5Cl][Sb2F11]2 exclusively of the C-F type (about 2 for each C atom of the five carbonyl groups) resulting in extended structures. The vibrational spectra for both [M(CO)5Cl]2+ cations (M = Rh, Ir) are assigned with the help of density functional calculations, which also provide intensities for IR and Raman bands. While [Rh(CO)5Cl]2+ is the first cationic carbonyl derivative of Rh(III), the vibrational and structural parameters for [Ir(CO)5Cl]2+ are compared to data for [Ir(CO)6]3+ and mer-Ir(CO)3(SO3F)3.
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Foerstner J, Kakoschke A, Wartchow R, Butenschön H. Reactions of Cyclopropenone Derivatives with a Cyclopentadienylcobalt(I) Chelate: Formation of a Cobaltacyclobutenone and a Transformation of 2,2-Dimethoxycyclopropenone to Methyl Acrylate at Cobalt. Organometallics 2000. [DOI: 10.1021/om0000818] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Braje W, Frackenpohl J, Schrake O, Wartchow R, Beil W, Hoffmann H. Synthesis of 10,11-DidehydroCinchona Alkaloids and Key Derivatives. Helv Chim Acta 2000. [DOI: 10.1002/(sici)1522-2675(20000412)83:4<777::aid-hlca777>3.0.co;2-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Frackenpohl J, Roper S, Hoffmann ΗMR, Wartchow R. Crystal structure of (1S,2R,5R,6R)-2-methoxy-6-(16-nitrophenylethynyl)-1-azabicyclo[3.2.2]nonane, C17H20N2O3. Z KRIST-NEW CRYST ST 2000. [DOI: 10.1515/ncrs-2000-0364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wartchow R, Frackenpohl J, Hoffmann HMR. Crystal structure of (1S,2R,4S)-2-bromomethyl-1-azabicyclo[2.2.2]·octan-5-one, C8H12BrNO. Z KRIST-NEW CRYST ST 2000. [DOI: 10.1515/ncrs-2000-0363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Stark CB, Pierau S, Wartchow R, Hoffmann HM. Chiral allyl cations are captured by furan with 100% stereoselectivity: synthesis of enantiopure 2-alkoxy-8-oxabicyclo. Chemistry 2000; 6:684-91. [PMID: 10807179 DOI: 10.1002/(sici)1521-3765(20000218)6:4<684::aid-chem684>3.0.co;2-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A low-temperature (-95 degrees C) protocol for intermolecular cycloadditions of furan to chiral silyloxyallyl cations in dichloromethane is described. Key precursors are open-chain, mixed a-ketoacetals, which are chiral. The resulting [4+3] cycloadducts are densely functionalized and are isolated as single enantiomers in high chemical yield. The yield of the cycloadducts increases with increasing dilution. Three and four stereogenic centres are created in one single step.
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Wirringa J, Wartchow R, Binnewies M. Crystal structure of cobalt chromium germanium, CoCrGe. ACTA ACUST UNITED AC 2000. [DOI: 10.1515/ncrs-2000-0202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Patzke GR, Wartchow R, Binnewies M. Refinement of the crystal structure of diindium disilicate, In2(Si2O7). Z KRIST-NEW CRYST ST 2000. [DOI: 10.1515/ncrs-2000-0111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wittenberg J, Hoffmann HMR, Wartchow R. Crystal structure of 1,8-dimethyl-7α-methoxy-10α-(triisopropylsilyloxy)- (2β) - 12-oxatricyclo[6.3.1.02,7] dodecane-3β,4α-diol, [(C3H7)3SiO](CH3)2(OH)2(OCH3)(C11H12O). Z KRIST-NEW CRYST ST 2000. [DOI: 10.1515/ncrs-2000-0177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gopal Dongol K, Krüger J, Schnebel M, Voigt B, Wartchow R, Butenschön H. Tricarbonylchromium complexes with methoxy substituted benzocyclobutenone and benzocyclobutenedione ligands. Inorganica Chim Acta 1999. [DOI: 10.1016/s0020-1693(99)00353-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Braje WM, Wartchow R, Hoffmann HMR. Struktur und Mechanismus in der Cinchonaalkaloidchemie: Ein 50 Jahre altes Fehlkonzept wird widerlegt. Angew Chem Int Ed Engl 1999. [DOI: 10.1002/(sici)1521-3757(19990903)111:17<2697::aid-ange2697>3.0.co;2-j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Braje WM, Wartchow R, Hoffmann HM. Structure and Mechanism in Cinchona Alkaloid Chemistry: Overturning a 50-Year-Old Misconception. Angew Chem Int Ed Engl 1999; 38:2539-2543. [PMID: 10508331 DOI: 10.1002/(sici)1521-3773(19990903)38:17<2539::aid-anie2539>3.0.co;2-c] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Long-standing errors of the supposedly established literature, including textbooks and data bases have been corrected: The structure of the hetero-cinchona bases in the crystal and in solution (see scheme) and the mechanism of their formation from quinine and quinidine have been elucidated.
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Bernhardt E, Bley B, Wartchow R, Willner H, Bill E, Kuhn P, Sham IHT, Bodenbinder M, Bröchler R, Aubke F. Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)6][Sb2F11]2, and -Hexafluoroantimonate(V), [Fe(CO)6][SbF6]2, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis. J Am Chem Soc 1999. [DOI: 10.1021/ja990958y] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gesing ΤM, Wartchow R. Crystal structure of hexasodium trizinc tetraarsenate trihydrate, Na6Zn3(AsO4)4 3H2O. Z KRIST-NEW CRYST ST 1999. [DOI: 10.1515/ncrs-1999-0203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Patzke G, Wartchow R, Binnewies M. Crystal structure of triholmium pentagallium dodecaoxide, Ho3Ga2(GaO4)3 and of tridysprosium pentagallium dodecaoxide, Dy3Ga2(GaO4)3. Z KRIST-NEW CRYST ST 1999. [DOI: 10.1515/ncrs-1999-0202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Uhl W, Hannemann F, Saak W, Wartchow R. Diazomethane Derivatives Bearing Dialkylaluminium or DialkylgalliumSubstituents – The Isomeric Diazomethane and Nitrile Imine Structures Realized by the Different Coordination Behavior of Aluminium and Gallium. Eur J Inorg Chem 1999. [DOI: 10.1002/(sici)1099-0682(199905)1999:5<771::aid-ejic771>3.0.co;2-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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