Chiral Biaryl Compounds Research Articles

Synthesis of Chiral Biaryl Compounds Through Cycloisomerization

Synthesis of Chiral Biaryl Compounds Through Cycloisomerization

Catalytic atropo-Enantioselective Preparation of Axially Chiral Biaryl Compounds

Abstract The atropo-enantioselective ring-opening of biaryl lactones with methanol was catalyzed by an optically active AgBF4–phosphine complex to afford axially chiral biaryl compounds. The addition of triisobutylamine provided a dramatic rate acceleration in the reaction. Various types of axially chiral biaryl compounds were obtained with high enantioselectivity.

Enantioselective Reduction of Biaryl Lactones via DKR

Chiral biaryl compounds are typically accessed by biaryl couplings followed by a resolution; a challenging approach in cases of hindered ortho-substituted aryl partners. The above strategy is advantageous since the biaryl coupling is effected on intramolecular aryl partners tethered by an ester function. The racemic atropisomer mixture is submitted to a dynamic kinetic resolution (DKR) where asymmetric reduction occurs at a temperature where rapid isomerization of the atropisomers can take place. Reduction of the matched atropisomer fully converts the racemic mixture into the desired enantiomer of the biaryl compound in high enantiomeric ecxess.

Catalytic atropo-Enantioselective Reduction of Biaryl Lactones to Axially Chiral Biaryl Compounds

The atropo-enantioselective borohydride reduction with dynamic kinetic resolution of biaryl lactones was catalyzed by an optically active beta-ketoiminatocobalt(II) complex to afford optically active biaryl compounds. Chiral HPLC analysis of the starting biaryl lactones was performed at various temperatures to determine suitable reaction conditions for dynamic kinetic resolution. Various types of axially chiral biaryl compounds were obtained with high enantioselectivity.

Asymmetric Synthesis of Antimicrotubule Biaryl Hybrids of Allocolchicine and Steganacin

The asymmetric synthesis of novel axially chiral biaryl compounds 5 a-f containing a seven- or eight-membered heterocyclic medium ring is described. These molecules can be considered to be structural hybrids of allocolchicine- and steganacin-type natural products. The synthesis featured an atropo-diastereoselective biaryl Suzuki coupling in which a benzylic stereocenter efficiently transferred its stereochemical information to the biaryl axis. The coupling conditions were optimized, and two biphenylphosphane ligands (DavePhos and S-Phos) were found to give the highest yields and diastereoselectivities. A three-element stereochemical model was proposed to explain the observed diastereoselectivities. In a second key step, the medium ring of the target molecules was formed by a stereoselective S(N)1-type cyclodehydration that probably involved a configurationally stable carbocationic intermediate, as supported by calculations. Alternatively, S(N)2-type cyclizations were employed on the same Suzuki coupling products to give the target molecules in a stereodivergent or stereoconvergent manner. These cyclization methods furnished the target hybrid analogues 5 a-f with ee values above 94 %. All analogues were evaluated as antimicrotubule agents and against a panel of cancer-cell lines using colchicine (1) and N-acetylcolchinol (3) as references. Promising activities were found for R,aR-configured compounds 5 a, b and 5 f; in particular, ethyl analogue 5 b showed a twofold antimicrotubule activity relative to colchicine.

An Efficient One-Pot Asymmetric Synthesis of Biaryl Compounds via Diels−Alder/Retro-Diels−Alder Cascade Reactions

[reaction: see text] A single-step chirality transfer method for the synthesis of axially chiral biaryl compounds by construction of the second aromatic ring via a Diels-Alder/retro-Diels-Alder cascade reaction is reported. This methodology should find broad application in the synthesis of natural products and asymmetric catalysts.

Atroposelective Synthesis of Axially Chiral Biaryl Compounds

AbstractFor Abstract see ChemInform Abstract in Full Text.

ChemInform Abstract: A Catalytic Asymmetric Suzuki Coupling for the Synthesis of Axially Chiral Biaryl Compounds.

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A Catalytic Asymmetric Suzuki Coupling for the Synthesis of Axially Chiral Biaryl Compounds

A Catalytic Asymmetric Suzuki Coupling for the Synthesis of Axially Chiral Biaryl Compounds

New method of kinetic resolution of axially chiral biaryl compounds using a sugar template.

New method of kinetic resolution of axially chiral biaryl compounds using a sugar template.

A new strategy for the synthesis of axially chiral biaryl compounds

Axially chiral compounds can be synthesized in high atropisomeric purity by aryl coupling of a conformationally locked dihydroxy-stilbenoids, which are readily available via Sharpless asymmetric dihydroxylation of olefin precursors.

Synthesis of Optically Active Polyamides Having Axially Dissymmetric 1,1′-Binaphthalene-2,2′-dicarboxylic Acid Component and Their Optical Resolution Ability as Chiral Adsorbent for HPLC

Abstract Optically active polyamides 4a–4c were synthesized from the polycondensation of axially dissymmetric 1,1′-binaphthalene-2,2′-dicarbonyl dichloride (2) with 1,4-benzenediamine, 1,6-hexanediamine, and 1,10-decanediamine, respectively. CD spectra of the polyamides 4a–4c are essentially the same as those of the corresponding model diamides 6a–6c prepared from 2 and benzenamine, 1-hexanamine, and 1-decanamine, respectively. This similarity indicates that the conformation of the 1,1′-binaphthalene-2,2′-dicarboxamide moieties of the polyamides 4a–4c in solution state are rather similar to those of the corresponding model diamides 6a–6c. Several axially chiral biaryl compounds and 3,5-dinitrophenylcarbamates (3,5-DNPCs) derived from 1-aryl-1-alkanols were resolved by HPLC equipped with the columns packed the chiral stationary phases (CSPs) prepared from 4a–4c adsorbed on spherical silica gel. A main control factor for the chiral discrimination seems to be the hydrogen bonding between the amide groups of the CSPs and the hydrogen-bonding sites of the atropisomeric biaryls. The donor–acceptor interaction between the binaphthalene moiety of the CSPs and the 3,5-dinitrobenzene moiety of the 3,5-DNPCs may also be important for the chiral discrimination of the 3,5-DNPCs.