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α-Allylation of 3 took place upon treatment with KHMDS followed by allylic halides in 82–87% ee in the absence of external chiral sources. A chiral nonracemic enolate with intramolecular aggregation (D) is expected to be an intermediate. [Copyright &y& Elsevier]

Abstract: Asymmetric Horner–Wadsworth–Emmons reactions of selected meso-α-dicarbonyl compounds with chiral phosphonate reagents, which possessed axially dissymmetric 1,1′-bi-2- or 8-naphthol at the carboxylate moiety as a chiral auxiliary, were examined. The reactions proceeded smoothly with good chemical yields as well as with high diastereoselectivities. Z-olefins were preferentially formed, and it was found that the free hydroxy group at the 2′- or 8′-position on the naphthalene ring plays a crucial role in the high diastereoselectivity, probably due to a complex-induced proximity effect. Mechanistic considerations are also described. [Copyright &y& Elsevier]

Abstract: Chiral 2,2′-dimethyl-1,1′-binaphthyl-8,8′-diamine 3b was synthesized via a diastereomeric resolution and determination of the absolute configurations, and the barriers compared for atropisomerization amongst binaphthyl skeletons. [Copyright &y& Elsevier]

The oxidative homocoupling of optically active binaphthalenes 1a-d with a stoichiometric amount of CuCl2 and amines afforded quaternaphthalenes 2a-d in up to 93% de. The high diastereoselectivities were achieved through three different pathways (epimerization of the axis together with diastereoselective crystallization, thermodynamic, and kinetic control pathways). The type of side chains on the naphthalene influenced which pathway dominates. Three pathways were applicable to octinaphthalenes (8a-d) and hexadecanaphthalene 10a with 46–99% de. The absolute configuration of the newly formed axial bond was determined by (1) X-ray crystallographic analysis, (2) transformation to known compounds 15 and 16, (3) CD spectra of oligonaphthalenes with two pyrene rings as exciton parts, and (4) the shift values in 13C NMR spectra of 13C-enriched derivatives 29–31 toward chiral shift reagent Eu(+tfc)3. [ABSTRACT FROM AUTHOR]

Various types of chiral host molecules 2–7 based on a phenolphthalein skeleton and two crown ethers were prepared for use in visual enantiomeric recognition, and we examined their enantioselective coloration in complexation with chiral amino acid derivatives 9–22 in methanol solution. Methyl-substituted host (S,S,S,S)-3 showed particularly prominent enantiomer selectivity for the alanine amide derivatives 11 and 12. A combination of methyl-substituted host (S,S,S,S)-3 with guest (R)-11 or (R)-12 developed a purple color, whereas no color development was observed with (S)-11 or (S)-12. On the other hand, phenyl-substituted host (S,S,S,S)-6 showed deeper coloration with a wide range of (S)-β-amino alcohols compared to that seen with host (S,S,S,S)-6 and the corresponding (R)-β-amino alcohols at 0 °C. Furthermore, absorbance inversion temperatures (AIT) were observed within the range of 0–50 °C in many cases. [ABSTRACT FROM AUTHOR]

Abstract: An efficient and convenient method for the synthesis of chiral triamines with two substituents at the α position to the terminal amino group (spermidine analogues) is described. These chiral N,N-bis(4-substituted-4-aminobutyl)amines may have anticancer activities. [Copyright &y& Elsevier]

The copper mediated oxidative coupling of optically active quaternaphthalenes having a 2-hydroxynaphthyl moiety gave configurationally defined optically active octinaphthalenes. The absolute configuration was determined by comparison with products of [6+2] coupling. The CD spectra of bi-, ter-, quater-, sexi- and octinaphthalenes suggested that the absolute configuration of the chiral axis could be deduced from the intensity of their Cotton effects. [Copyright &y& Elsevier]

The synthesis and resolution of 3,3′-bis(benzyloxy)-1,1′-binaphthalene-2,2′-diol 1 is described. A diastereomeric mixture of 7 (derived from (±)-1 and Boc-Ala-OH) was separated using crystallization and column chromatography. [Copyright &y& Elsevier]

Two binaphthyl crown receptors containing phenylboric acid 2 and 2,4-dinitrophenylurea 3 as lariat parts were prepared from the optically active binaphthyl crown alcohol 1 in two and four steps, respectively. Host 2 showed a 30% extraction efficiency for GABA by a solid–liquid extraction method in DMSO. Chromogenic Host 3 discriminated the guest linear amino acid by molecular length and the information was revealed through color changes. [Copyright &y& Elsevier]

Chiral 4-pyrrolidinopyridine analogues 8–13 with two distinct functional side chains at C(2) and C(4) of the pyrrolidine ring were prepared from 4-hydroxy-l-proline. We examined desymmetrization of meso-1,3-cyclohexanediol through enantioselective acylation using these catalysts and found that introduction of a C(4)-side chain was effective for improving both the chemo- and enantioselectivity of acylation. [Copyright &y& Elsevier]

Two strategies were introduced for the control of enantioselectivity of alkylation of phenylalanine derivatives by regulation of the aggregate structure of chiral enolate intermediates. Use of amino acid-dimers, 6 and 15, was effective to minimize solvent- and electrophile-dependency of enantioselectivity of the alkylation. α-Allylation of 20 proceeded in improved selectivity of 82–88% ee under the control of aggregation of the intermediary enolate. [Copyright &y& Elsevier]

Several functional groups were introduced on the upper rim of (lower rim free) homooxacalix[3]arene for the first time. The swinging nitrohomooxacalix[3]arene host 1 was fixed in the cone conformation by complexation with n-hexylamine. [ABSTRACT FROM AUTHOR]

The new ditopic receptors 1–3 consisting of a meso-ternaphthalene backbone and two crown ether rings have been synthesized. Hosts 2 and 3 have been shown to selectively complex and transfer the dipicrates, 1,9-diaminononane and 1,10-diaminodecane, from aqueous solution into the organic phase. [Copyright &y& Elsevier]

Novel perhydro-indanones and -naphthalenones having a quaternary stereogenic carbon and tetrasubstituted olefinic linkage were prepared via asymmetric intramolecular Horner–Wadsworth–Emmons reactions. The optically active binaphthyl phosphonates were connected with the 2-substituted cyclopenta- or cyclohexa-1,3-dione through the linker arm and the successive base treatment of the products with diethylzinc led to cyclization reactions with concomitant differentiation of diastereotopic carbonyl groups to afford the non-racemic title compounds in good enantiomeric excess. The absolute structure of the cyclized product was determined by X-ray analysis of its derived bromide. [Copyright &y& Elsevier]

An optically active proton-ionizable lariat crown ether derivative 2 was prepared. Host 2 displays enantiomeric selectivity toward phenylglycinol (Klarge/Ksmall=3.2) and phenylalaninol (Klarge/Ksmall=1.7). The key intermediate 1 was synthesized in two steps from commercially available binaphthol in 30% yield. [Copyright &y& Elsevier]

Describes the synthesis of the skeletal structure of tetraoxacalix[3]arenes. Structural characterization of the compound; Ion-binding properties of the structure; Investigation of calixarenes as host compound; Preparation of calixarene analogues; Employment of X-ray crystallographic analysis.

Presents a study in which the construction of several hexahomooxacalix[3]arene derivatives 23-38, was achieved by an acid-catalyzed cyclization of the corresponding linear trimers. Description of research materials and methods used; Conformation of hexahomooxacalix[3]arenes in the solid state; Conclusion of the study.

The helical structure is one of the most ordered structures and packs molecular information into a restricted space. In the field of supramolecular chemistry, these helical structures have attracted considerable attention and various artificial helical molecules have been synthesized. The article focuses on optically active rod-shaped 2,3-dioxyfunctionalized naphthalene connected at their 1,4-positions. Important characteristics of these oligonaphthalenes suggest that their frameworks are rigid in the rod direction, they have chirality and some degree of flexibility around the axes and functional groups can be introduced into scaffolding 2,3-dioxy groups.

Host 1 based on the phenolphthalein skeleton and two crown ether moieties demonstrated opposite behaviors toward sodium and potassium cations caused by bidirectional complexation. [reaction: see text]

The helical structure of the chiral nematic phases (cholesterics) obtained by doping nematic solvents with chiral non-racemic compounds is a macroscopic proof of the solute chirality. Oligonaphthalene (tetra-, hexa-, octa-) derivatives linked at the 1,4-positions have been used as chiral dopants: When the chirality axes are configurationally homogeneous (that is, all-S), the molecular structures correspond to right-handed helices. Yet, we have found series of derivatives with the surprising property that the handedness of the induced cholesteric phase alternates from positive to negative and to positive again, on passing from tetra- to hexa- and to octanaphthalene. A comparison with oligonapthalene derivatives, which do not exhibit this twisting ability, points to the importance of the substitution pattern. Both the possibility of inducing oppositely-handed cholesteric phases by homochiral helices of different length, and the role played of substituents, are confirmed by calculations performed with the surface chirality model.

An optically active spiropyran 1 with a binaphthol moiety as a chiral source was synthesized. The colored merocyanine form of (R)-1 obtained by the UV irradiation remained in the presence of D-amino acids longer than with L-amino acids., (Copyright 2002 Wiley-Liss, Inc.)

[structure: see text] The artificial host molecule 1, consisting of homooxacalix[3]arene and pyridinium N-phenolate dye (Reichardt dye E(T)1) has been prepared. Host 1 contains a proton-ionizable phenol group that acts as a chemical switch to generate color change against alkaline metals and various kind of amines.

[structure: see text] A receptor 1 with phenolphthalein and two crown ethers in the molecule develops brilliant purple color in the presence of dipeptides with a specific amino acid-sequence containing a C-terminal lysine. This type of color development could be extended to the detection of oligopeptides of a specific sequence at the N-terminal such as scyliorhinin I and APP(770)(394-410).

[reaction: see text] A total synthesis of spirotryprostatin B was accomplished via asymmetric nitroolefination as a key step.