The reductive cyclization of 8,8′-bisbromomethyl-1,1′-binaphthyl

Reductive cyclization of the title compound to the corresponding dinaphthocycloöctatriene is a facile process. The dinaphthocycloöctatriene does not undergo ring inversion on the NMR time scale, even at elevated temperatures.     

A highly efficient method for the resolution of 8,8′-dihydroxy-1,1′-binaphthyl

The diastereomeric mixture of monoesters of racemic 8,8′-dihydroxy-1,1′-binaphthyl and N-CBZ-l-proline was easily separated. Each diastereomer gave enantiomerically pure (R)- or (S)-8,8′-dihydroxy-1,1′-binaphthyl in good yields after hydrolysis.     

8,8′-Bis(diphenylphosphinomethyl)-1,1′-binaphthyl. Synthese und Konformation

Summary The title compound3 was prepared from 8,8-Bis(bromomethyl)-1,1-binaphthyl (1) in two steps in approx. 10% overall yield. The crystal structure of the intermediate phosphinoxide2 was determined. Attempts to prepare chelate complexes of3 with Ni(II) or Pd(II) failed.

     

Synthesis and liquid crystalline behavior of a series of ferrocene 1,1′-bis-azino-derivatives

A series of liquid-crystalline ferrocene derivatives, Fe{C₅H₄-C(CH₃)=N-N=CH-C₆H₃(X)-OOC-C₆H₄-OC _n H_2n+1}₂ (X = H, OH;n = 3 to 12), were obtained by the condensation of 1,1 -bishydrazondiacetylferrocene withp-alkoxybenzoyloxybenzaldehides. According to DSC and polythermic microscopy, all of the compounds exhibit an enantiotropic nematic mesophase in the 150–230 °C temperature range. A polycrystalline transition precedes the nematic transition. The liquid crystalline properties of the obtained compounds were investigated with respect to the number of carbon atoms in the terminal alkyl chain and the terminal hydroxyl group. The composition and structure of the obtained compounds were determined by elemental analysis and IR and NMR spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–361, February, 1995.This work was carried out with financial support from the Russian Fundation for Basic Research (Project No. 94-03-08978).     

Asymmetric Synthesis and Characterization of Chiral 2,2′‐Diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene

Abstract

rac‐2,2′‐Diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene was synthesized from diethyl 2‐aminoazulene‐1,3‐dicarboxylate and was optically resolved into two enantiomers of S‐form and R‐form. The enantioselective oxidative couplings with two chiral amines [(?)‐sparteine and (R)‐(+)‐α‐methylbenzylamine] and ferric chloride catalyst, and the asymmetric couplings with two chiral oxovanadium(IV) complexes of ethyl 2‐amino‐4‐phenylazulene‐1‐carboxylate, easily yielded chiral 2,2′‐diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene. Therefore, the introduction of two phenyl groups at the 8‐ and 8′‐postions of each azulene ring using phenyl magnesium bromide via an addition–oxidation–decarboxylation mechanism resulted in 1,1′‐biazulene forming a chiral C₂ axis.     

Structures of the crystalline supramolecular associates of imidazole with 1,1′-binaphthyl-8,8′-dicarboxylic acid and 2,2′-dihydroxy-1,1′-binaphthyl. Spatial similarity of the acid associate crystal packing to the active site of a serine protease

Abstract

Crystal structure analysis of the imidazole associates with 1,1′-binaphthyl-8,8′-dicarboxylic acid (1), [1a, triclinic, P1, a = 7.569(4), b = 8.393(2), c = 8.634(1) Å, α = 93.21(2), β = 106.88(3), γ = 105.17(3)°, D_c = 1.36 g/cm³, Z = 1, R = 0.045 for 1031 data] and with 2,2′-dihydroxy-1,1′-binaphthyl (2), [2a, tetragonal P4₁2₁2, a = 8.519(1), c = 29.821(2), D_c = 1.30 g/cm³, Z = 4, R = 0.051 for 1236 reflections] revealed 1:1 and 1:2 stoichiometry, respectively. Spontaneous resolution occur during crystallization in both compound crystals. 1a is a salt-like associate with hydrogen bonds between the carboxylate and imidazolium ion pairs while the neutral 2a has also well defined hydrogen bonds between host and guest molecules. In a modeling experiment corresponding Brookhaven Protein Data Bank atomic coordinates from the active site of the bacterial serine protease enzyme Subtilisin BPN were fitted to the crystal packing of the small molecule associate 1a crystal. The relative displacement of the ion pair components and a symmetry related carboxyl function in 1a has fair steric resemblance to similar moieties in the active site of Subtilisin (Δ_ave = 0.24 Å for 9 fitted atoms). The agreement in the results of two fully independent and totally different (i.e. a native protein active site and an artificial small molecule associate) crystal structure determinations underlines the assumed conceptual similarity of crystals (“giant supramolecules”) to protein sequences optimized through evolution.     

Gold-Catalyzed Atroposelective Synthesis of 1,1′-Binaphthalene-2,3′-diols

A highly atroposelective (up to 97 % ee) Au-catalyzed synthesis of 1,1′-binaphthalene-2,3′-diols is reported starting from a range of substituted benzyl alkynones. Essential for the achievement of high enantioselectivity during the key assembly of the naphto-3-ol unit is the use of TADDOL-derived α-cationic phosphonites as ancillary ligands. Preliminary results demonstrate that the transformation of the obtained binaphthyls into axially chiral monodentate phosphines is possible without degradation of enantiopurity.     

Novel Synthesis of Phosphorazolides and Phosplior-Anilidates by Reaction of Trimethylsilylphosphites with 1,1′-Oxalyldiazolides or 1,1′-Oxalyldianilidates

Abstract

Continuing our studies on new reaction of trimethylsilylphosphites 1 we now report the conversion of compounds 1 to the corresponding phosphorazolides or phosphoranilidates by the reaction of readily available trimethylsilylphosphites 1 and 1,l'-oxalyldiazolides or anilidates.     

Supramolecular architecture of diammonium ferrocene-1,1′-diyldiphosphinates

Diammonium ferrocene-1,1′-diyldi(H-phosphinate) (1) and diammonium ferrocene-1,1′-diylbis(phenylphosphinate) (2) were obtained for the first time and structurally characterized. Compound 1 shows a supramolecular 3D structure in the crystal; the structure is stabilized by hydrogen bonds between the layers of ammonium cations and the layers of ferrocene-1,1′-diyldiphosphinate anions. The more hydrophobic and sterically crowded ferrocene-1,1′-diylbis(phenylphosphinate) anion of compound 2 together with ammonium cations and solvate water molecules forms supramolecular 2D layers in the crystal.     

Chiral enrichment of 2-amino-2′-hydroxy-1,1′-binaphthyl

A new synthetic procedure for the formation of 2-amino-2′-hydroxy-1,1′-binaphthyl, and a new purification procedure through the formation of Schiff bases, purification of the Schiff bases, and breakdown of the Schiff bases through amine exchange, are described. Through the new purification procedure, greater than 99% purity of the compound can be obtained easily and reliably. A set of procedures were examined to compare the efficiency and reliability to resolve 2-amino-2′-hydroxy-1,1′-binaphthyl into enantiomers. A new procedure was discovered to enrich enantiomeric excess from less than 10% to 95–99% in one step. Even a racemic mixture from an achiral procedure can be enriched to 67% e.e. in about 4% yield. The X-ray crystal structure of the racemic mixture [rhombohedral, space group Iba2, a=15.718(2) Å, b=21.703(2) Å, c=8.5398(9) Å, V=2913.2(5) ų, R1=0.0705, Z=8, d_calcd=1.301 g/cm³, F(000)=1200 e] was solved to elucidate the intriguing behavior of this compound.     

Unexpected reactivity of the 2′-carboxyl functionality in rhodamine dyes

Contrary to previous literature reports, the reactivity of the 2′ carboxylic acid in rhodamine dyes was found to be much more reactive than anticipated. Typically, the 4′- or 5′-carboxy functionality in dicaboxyrhodamines is targeted for bioconjugation use due to the supposed unreactivity of the 2′ carboxylic acid. Reactive esters of 2′-carboxyrhodamine dyes lacking the 4′(5′)-carboxy substitutions permit a simplified synthesis of single isomer dyes but possess similar reactivities useful for labeling studies.     

Stereoselective synthesis of uncommon α,α′-dialkyl-α-aminoacids. Part 1

The alkylation of the diastereomeric mixture of chiral morpholinone derivatives 4 and 5 occurs with good yield and trans induction. Cleavage of the alkylated products 6a,b,c,e gives enantiomerically pure uncommon (and sterically constrained) α,α′-dialkyl-α-aminoacids. The absolute configuration of the new stereocentres of 4, 5, 6 and 7 has been assigned on the basis of the ¹H-NMR spectra and NOE measurements.     

The crystal and molecular structures of 1,1′-divinyl-2,2′-biimidazolyl

The crystal and molecular structures of 1,1-divinyl-2,2-biimidazolyl (L) were determined by x-ray crystallographic analysis. It was established that the molecule of L has crystallographic symmetry 2 and a cisoid conformation with an angle of rotation of 128° between the imidazole rings. The length of the C²-C² bond is increased to 1.485(11) Å compared with the length of the analogous bond in unsubstituted 2,2-biimidazolyl (1.423 Å). Localization of the N=C multiple bond is observed [1.297(9) Å]. The other N-C bonds of the ring are almost equalized (1.374 Å) and are close to the standard values for bonds of the C _sp ²-N type in imidazoles. The angle between the plane of the heterocycle and the plane passing through the atoms of the vinyl group amounts to 7°.N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow. Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1376–1380, June, 1992.     

Resolution of 8′-alkoxy- and hydroxy-1,1′-binaphthalen-8-ols

Enantiopure 8′-ethoxy-, 8′-hydroxy-, and 8′-methoxy-1,1′-binaphthalen-8-ol were readily resolved by separating the corresponding chiral camphanic esters [derived from the esterification of the alcohols with (−)-(1S)-camphanic chloride] based upon their differing solubility in diethyl ether and their differing chromatographic behavior.     

Molecular structures of 8,8′-dithioureido-2,2′-binaphthalene derivatives and their anions recognition: an ONIOM investigation

The structures of 8,8′-bis(3-phenylthioureidomethyl)-2,2′-binaphthalene (1), 8,8′-bis(3-butylthioureidomethyl)-2,2′-binaphthalene (2) and their complexes with anionic guests such as carboxylate ions (acetate, oxalate, malonate, succinate, glutarate, adipate, pimelate, suberate, and azelate), inorganic oxygen-containing anions (nitrate, sulfate, bicarbonate, hydrogen phosphate, and dihydrogen phosphate), and halide ions (fluoride, chloride, and bromide) were obtained using the ONIOM approach. The binding abilities of receptors 1 and 2 to anionic species in terms of binding energy, thermodynamic properties, and selectivity coefficient were obtained at the ONIOM(B3LYP/6-31G(d):AM1) and BSSE-corrected B3LYP/6-31G(d)//ONIOM(B3LYP/6-31G(d):AM1) levels of theory. The multipoint hydrogen bonding between receptors (either the receptor 1 or 2) and anionic guests were found. The hydrogen phosphate is the most preferable ion to bind with either the receptor 1 or 2.     

The molecular structure and conformation of 1,1′-dimethyl-bicyclopropyl

The molecular structure and conformation of 1,1′-dimethyl-bicyclopropyl have been studied by the gas electron diffraction method, extended by normal coordinate and molecular mechenics calculations. The experimental data are in accordance with all molecules having the gauche conformation, with a dihedral angle of 58°.     

Stereoselective Synthesis of 1,1′-Disaccharides by Organoboron Catalysis

The highly stereoselective synthesis of 1,1′-disaccharides was achieved by using 1,2-dihydroxyglycosyl acceptors and glycosyl donors in the presence of a tricyclic borinic acid catalyst. In this reaction, the complexation of the diols and the catalyst is crucial for the activation of glycosyl donors, as well as for the 1,2-cis-configuration of the products. The anomeric stereochemistry of the glycosyl donor depends on the employed glycosyl donor. Applications of the produced 1,1′-disaccharides are also described.