Enantiomerentrennung und chiroptische Eigenschaften eines 2,3-Dihydrobilatriens-abc

The enantiomers of the 2,3-dihydrobilatriene-abc1 have been separated by recycling chromatography on triacetylcellulose. Comparison of their chiroptical properties with those of amino acid substituted analogues, like3, reveals the chirality of center 3 to be of minor influence on the values. Stabilization of a definite helical conformation of these pigments seems to depend on this influence together with an appropriate dipole-dipole interaction.

     

Luteochrome; spektroskopische,chiroptische und chromatographische Eigenschaften

Two Optically Active Luteochromes: Preparation, Spectra and Chiroptical and Chromatographic Properties Selective rearrangement of (5R,6S,5′ R,6′S)-5,6:5′, 6′ -diepoxy-5,6,5′, 6′ -tetrahydro- β,β -carotene with the aid ofan ethereal solution of malonic acid leads to the mixture of the C(8′)-epimeric luteochromes. HPLC separation gave the pure isomers. This is the first report on th preparation of optically active luteochromes.     

Optisch aktive O-silyl-β-dicarbonylverbindungen : I.Darstellung und struktur

The reaction of optically active methylphenyl-α-naphthylchlorosilane with acetylacetone, ethyl acetoacetate, diethyl malonate, ethyl butyroacetate, ethyl benzo-acetate, and benzoylacetone in the presence of sodium or triethylamine leads to the formation of optically active O-silyl-β-dicarbonyl compounds(I)–(VI) with inversion of configuration. The compounds (I)–(VI) are obtained as cis-trans mixtures, the cis-trans-ratio depending on the preparative conditions. At room temperature, the cis-isomer of (I) exhibits rapid intramolecular silyl group migration from one O-atom to the other with retention of configuration. The trans-isomers of (I)–(VI) are also able to exchange silyl groups, but by intermolecular transfer and obviously with inversion of configuration. On standing for a longer time or on heating to ca. 190° a cis-trans-rearrangement, which leads to racemisation, can be observed for all compounds.     

Optisch aktive Ubergangsmetall-Komplexe XXI. Optisch aktive komplexe mit vier verschiedenen liganden am titanatom

Chiral C₅H₅(C₉H₇Ti(Cl)SCH(CH₃)₂ shows diastereotopic CH₃ resonances; the diasteroisomers of C₅H₅(CH₃C₅H₄Ti(Cl)OC₁₀H₁₉ could be separated by fractional crystallisation.     

Optisch aktive übergangsmetall-komplexe XX. Optisch aktive cyclopentadienyl-perfluoropropyl-kobalt-komplexe mit zweizähnigen schiff-basen

In the reaction of C₅H₅ Co(C₃F₇)(CO)I with the Schiff base NN′, derived from S-(-)-?-phenylethylamine and pyridine carbaldehyde-2, the salt [C₅H₅Co(C₃F₇)NN′]⁺ I^? (Ia,b) is formed, which can be transformed to [C₅H₅ Co(C₃F₇)NN′]⁺ PF₆^? (IIa,b). The sodium salt Na⁺ [NN″]^? of the Schiff base, derived from S-(-)-α-phenylethylamine and pyrrol carbaldehyde-2, in the reaction with C₅H₅ C0(C₃F₇)(CO)I yields the neutral complex C₅H₅ Co(C₃F₇)NN″ (IIIa,b). The diastereoisomeric pairs IIa,b and IIIa,b are separated by fractional crystallisation and chromatography respectively into the optically pure components which differ in their ¹H NMR spectra. The IR, UV, CD, mass spectra and optical rotations of the new compounds IIa, IIb, IIIa and IIIb are compared.     

Ptisch aktive übergangsmetall-komplexe : XVII. Optisch aktive oktaedrische carbonyl-komplexe von chrom,molybdän und wolfram

Substitution of 3 CO groups in cis position to each other in M(CO)₆ (M = Cr, Mo, W) by 3 ligands different from each other gives the chiral molecules cis-(CO)₃ML₁L₂L₃. If instead of L₁L₂ the Schiff base of pyridine-2-carbaldehyde with (-)-α-phenylethylamine and instead of L₃ triphenylphosphine is used, diastereoisomers are obtained which differ in the configuration at the metal atom. The diastereoisomeric pairs VIa–VIb, VIIa–VIIb and VIIIa–VIIIb can be separated into their (+)-and and (-)-rotating components by fractional crystallisation.     

Optisch aktive O-silyl-β-dicarbonylverbindungen : II. Reaktionen

Nucleophilic substitution reactions at the silicon atom of optically active O-silyl-β-dicarbonyl compounds are investigated. The solvolyses with water or methanol probably lead to inversion of configuration, which is masked in most cases by racemisation. Reactions with acid chlorides in all cases result in inversion of configuration. The silyl derivatives of ethyl acetoacetate or ethyl butyroacetate and LiAlH₄ react with inversion, but those of acetylacetone, diethyl malonate, ethyl benzoacetate or benzoylacetone with retention of configuration at the silicon atom.     

Optisch aktive 9,9′-Spirobifluoren-Derivate

The optically active compounds XXIII, XXIV, and XXV, named vespirenes, have been synthetized as first examples of compounds containing a single chirality centre of the type X(A₄). The analogous optically active 9,9′-spirobifluorene derivatives XXI, XXVI, and XXVIII have been prepared for comparison of their chiroptic properties with those of vespirenes.     

Stereochemie von Metallocenen, 33. Mitt.: Optisch aktive Aryl-ferrocene, 4. Mitt.: Optisch aktive Ferroceno[b]indene,-hydrindene und verwandte Verbindungen

Zusammenfassung Optisch aktives Ferroceno[b]indenon (2) wurde durch kinetische Racematspaltung des gut zugänglichenendo-Ferroceno-indenols3 mit (+)--Phenylbuttersäure-anhydrid in optischen Ausbeuten um 20% erhalten. Aus den Ergebnissen dieser Racematspaltung (auch für dasexo-Carbinol5) ließen sich auf Grund der bekannten Absolutkonfiguration (+)-(1R)-2 die relativen stereochemischen Größen von Ferrocen und Benzol (Fc>Phenyl) erstmals festlegen.Mehrere Folgeprodukte von (+)-2 (darunter Ferrocenohydrindene) wurden dargestellt und ihre chiroptischen Eigenschaften mit jenen von strukturell verwandten Ferrocenderivaten (wie13–18) verglichen (und diskutiert). DieCD-Kurven wurden einer Bandenanalyse unterworfen.

---

Stereochemistry of metallocenes, XXXIII. (ferrocenes, LIV). Optically active arylferrocenes, IV: Optically active ferroceno[b]indenes, hydrindenes, and related compounds

Optically active ferroceno[b]indenon (2) was obtained by kinetic resolution of the easily accessibleendo ferroceno indenol (3) with (+)--phenylbutyric anhydride with optical yields of 20%. From the results of this resolution (also for theexo-carbinol5) on the basis of the known absolute configuration (+)-(1R)-2 the relative stereochemical sizes of ferrocene and benzene could be established for the first time:Fc>phenyl.Several subsequent products of (+)-2 (amongst them ferroceno hydrindenes) were prepared and their chiroptical properties compared with those of structurally related ferrocenes (such as13–18) (and discussed). TheCD-curves were subjected to a band analysis.

---

---

Mit 6 Abbildungen

---

Herrn Prof. Dr.M. Pailer in herzlicher Verbundenheit zum 60. Geburtstag gewidmet.

---

32. Mitt. (3. Mitt. über optisch aktive Aryl-ferrocene, 53. Mitt. über Ferrocenderivate):H. Falk, H. Lehner undK. Schlögl, Mh. Chem.101, 967 (1970).     

Optisch aktive 1- und 2-substituierte 9,10-Dihydro-9,10-äthanoanthracene

Zusammenfassung Racematspaltung der 9,10-Dihydro-9,10-äthanoanthracen-1-und 2-carbonsäuren bzw.-(-oxobuttersäuren) (2 a, 2 b bzw.8 a, 8 b) und geeignete Folgereaktionen machten optisch aktive monosubstituierte Derivate von 9,10-Dihydro-9,10-äthanoanthracen,1 (wie die Acetyl-, Formyl- und Methylderivate) sowie aus den buttersäuren9 (erhalten aus8) auch cyclische Ketone (10 und11) zugänglich. Die konfigurative Korrelation der beiden Reihen (a undb) gelang über die Schlüsselsubstanz (+)-1,2,3,4,7,12-Hexahydro-7,12-äthanobenzo[a]-anthracen (12), woraus sich auch die optische Reinheit aller Folgeprodukte ergab.Die absolute Konfiguration wurde durch kinetische Racematspaltung sowohl der Carbonsäure2 a als auch eines mit2 a (und2 b) korrelierten Carbinols14 (nachHoreau) für alle beschriebenen Derivate von1 als (+)-(9R) ermittelt.Neben den []_D-Werten wurden auch dieCD-Spektren einiger Derivate von1 gemessen. Diese chiroptischen Daten werden kurz diskutiert.

---

Optically active 1- and 2-substituted 9.10-dihydro-9.10-ethanoanthracenes; Preparation, chiroptical properties, configurational correlations and absolute configurations

Optically active monosubstituted derivatives of 9.10-dihydro-9.10-ethanoanthracene (1)—such as the acetyl, formyl and methyl derivatives—were prepared by optical resolutions of the carboxylic acids2 a and2 b and the -oxobutyric acids8 a and8 b, resp., and suitable subsequent reactions, whilst from the butyric acids9 (accessible from8) also cyclic ketones (10 and11) were obtained. The configurative correlation of both series (a andb) was achievedvia the key substance (+)-1.2.3.4.7.12-hexahydro-7.12-ethanobenzo[a]anthracene (12) wherefrom also the optical purities of all compounds were deduced.The absolute configurations of all described derivatives of1 were established as being (+)-(9R) by kinetic resolutions both of the carboxylic acid2 a and of a carbinol14 (correlated with2 a and2 b) according toHoreau's method.Besides the []_D-values also theCD-spectra of some typical derivatives of1 were recorded. These chiroptical properties are briefly discussed.

---

---

Mit 1 Abbildung