Chiral Dicarboxylic Acid Research Articles

ChemInform Abstract: Axially Chiral Dicarboxylic Acid Catalyzed Asymmetric Semipinacol Rearrangement of Cyclic β‐Hydroxy‐α‐diazo Esters.

AbstractTreatment of the intermediate β‐keto esters according to B) causes decarboxylation to produce cycloheptanone systems.

Synthesis and characterization of new optically active poly(amide-imide)s derived from N,N′-(pyromellitoyl) bis-L-tyrosine and various diamines

Five new optically active poly(amide-imide)s(PAIs) 5a–e were prepared by direct polycondensation reaction of N,N′- (pyromellitoyl) bis-L-tyrosine 3 as chiral dicarboxylic acid with various aromatic diamines 4a–e. Triphenylphosphite(TPP)/pyridine(py) in the presence of calcium chloride (CaCl2) and N-methyl-2-pyrrolidone (NMP) were successfully applied to direct polycondensation reaction. The resulting new polymers were obtained in good yields with inherent viscosities ranging between 0.48 dL/g and 0.6 dL/g. They were analyzed with a C.H.N. elemental analyzer, FTIR, 1H-NMR, UV-VIS spectroscopy and polarimeter (specific rotation measurement, [α] 25D ). Thermogravimetric analysis (TGA) indicated that the residual weight percentage of polymers at 600 °C were between 48.66 % and 64.21 %, which showed their thermal stability. These polymers are attractive to be used as packing materials in chromatography columns for separation of enantiomers.

ChemInform Abstract: A Catalytic Asymmetric Ugi‐Type Reaction with Acyclic Azomethine Imines.

AbstractIn the presence of axially chiral dicarboxylic acid BNDA as catalyst, 2‐benzoyloxyaryl isocyanides react with azomethine imines generated in situ from aldehydes and benzhydrazide (II), to give oxadiazine derivatives (IV).

軸不斉ジカルボン酸を用いた触媒的不斉合成法の開発

In the past decade, chiral Brønsted acid catalysis has become a leading tool to achieve catalytic asymmetric transformations. As a source of Brønsted acids, poorly acidic hydrogen bonding donors like (thio)ureas and alcohols had been used in the early study, and strongly acidic phosphoric acids then emerged as an indispensable option. We became interested in the use of chiral carboxylic acids, as they have a distinct acidity which cannot be provided by other Brønsted acids. To this end, we developed axially chiral dicarboxylic acids bearing two carboxylic acids at the 2,2’-positions of a binaphthyl unit, and succeeded in applying these catalysts to a variety of asymmetric transformations.

Axially chiral dicarboxylic acid catalyzed asymmetric semipinacol rearrangement of cyclic β-hydroxy-α-diazo esters

The development of axially chiral dicarboxylic acid catalyzed desymmetrizing asymmetric semipinacol rearrangement of symmetrically substituted six-membered cyclic β-hydroxy-α-diazo esters is reported as a means to give chiral cycloheptanones with good enantioselectivities.

A Catalytic Asymmetric Ugi‐type Reaction With Acyclic Azomethine Imines

An unconventional Ugi: A catalytic asymmetric Ugi-type reaction can be realized by use of N'-alkylbenzohydrazide, instead of a conventional amine, in the presence of an axially chiral dicarboxylic acid. The reaction proceeds through a key acyclic azomethine imine intermediate, which has recently emerged as a promising electrophile in asymmetric catalysis.

ChemInform Abstract: Modular Synthesis of Axially Chiral 3,3′‐Disilyl Dicarboxylic Acids by Silalactones.

AbstractThe method is based on the dehydrogenative silalactonization of axially chiral dicarboxylic acid (I) with chlorohydrosilanes, followed by ring opening with Grignard compounds.

Chiral self-assembly of triorganotin complexes: Syntheses, characterization, crystal structures and antitumor activity of organotin(IV) complexes containing ( R)-(+)-methylsuccinic acid, ( S)-(+)-methylglutaric acid and l-(−)-malic acid ligands

Six new chiral triorganotin(IV) complexes, {(R 3Sn) 2[C 3H 6(COO) 2]} n (R = Me: 1; Bu: 2), {(R 3Sn) 2[C 4H 8(COO) 2]} n (R = Me: 3; Bu: 4), and {(R 3Sn) 2[C 2H 4O(COO) 2]} n (R = Me: 5; Bu: 6) have been prepared by treatment of ( R)-(+)-methylsuccinic acid, ( S)-(+)-methylglutaric acid and l-(−)-malic acid, with the corresponding R 3SnCl (R = Me, Bu) and sodium ethoxide in methanol. All the complexes were characterized by elemental analysis, FT-IR, NMR ( 1H, 13C, 119Sn) spectroscopy and TGA. Except for 3, all of the complexes were also characterized by X-ray crystallography. The structural analyses reveal that complexes 1 and 5 have 2D network structures in which ( R)-(+)-methylsuccinic acid and l-(−)-malic acid act as tetradentate ligands coordinated to trimethyltin(IV) ions. Complexes 2 and 4 have 3D metal–organic framework structures in which the deprotoned acids serve as tetradentate ligands. Complex 6 adopts a 1D zigzag chain structure and forms a 2D supramolecular framework through intermolecular C–H⋯O interactions. In addition, the antitumor activities of complexes 1– 6 have been studied. We also have measured the specific rotation of the chiral dicarboxylic acids and the organotin derivatives.

Generation and exploitation of acyclic azomethine imines in chiral Brønsted acid catalysis

Successful implementation of a catalytic asymmetric synthesis strategy to produce enantiomerically enriched compounds requires the adoption of suitable prochiral substrates. The combination of an azomethine imine electrophile with various nucleophiles could give straightforward access to a number of synthetically useful chiral hydrazines, but is used rarely. Here we report the exploitation of acyclic azomethine imines as a new type of prochiral electrophile. They can be generated in situ by the condensation of N'-benzylbenzoylhydrazide with a variety of aldehydes in the presence of a catalytic amount of an axially chiral dicarboxylic acid. By trapping these electrophiles with alkyl diazoacetate or (diazomethyl)phosphonate nucleophiles, we produced a diverse array of chiral α-diazo-β-hydrazino esters and phosphonates with excellent enantioselectivities.

ChemInform Abstract: Asymmetric Inverse‐Electron‐Demand 1,3‐Dipolar Cycloaddition of C,N‐Cyclic Azomethine Imines: An Umpolung Strategy.

AbstractAxially chiral dicarboxylic acids (I) exhibit high catalytic activity in the title reaction of dihydroisoquinoline derivatives (II) with vinyl ether (III) to give the cycloadducts exclusively as exo‐isomers with excellent enantioselectivities.

Synthetic Application and Structural Elucidation of Axially Chiral Dicarboxylic Acid: Asymmetric Mannich-type Reaction with Diazoacetate, (Diazomethyl)phosphonate, and (Diazomethyl)sulfone

The past decade has witnessed the burgeoning research fields of chiral Brønsted acid catalysis. However, carboxylic acids, arguably the most general acids in organic chemistry, have rarely been used as chiral Brønsted acid catalysts. In this context, we developed axially chiral dicarboxylic acid and evaluated its catalytic activity in asymmetric Mannich-type reaction of aromatic aldehyde-derived N-Boc imines and tert-butyl diazoacetate. To demonstrate the remarkable generality of this catalytic system, tert-butyl diazoacetate was replaced with its phosphorus and sulfur analogues, (diazomethyl)phosphonate and (diazomethyl)sulfone, by which synthetically valuable chiral β-amino phosphonates and β-amino sulfones could be obtained with high enantioselectivities under identical reaction conditions. X-ray crystallographic analysis of axially chiral dicarboxylic acid complexed with a pyridine derivative revealed its unique internal hydrogen bonding, a property that serves as a basis for its distinctive acidity and chiral scaffold.

Modular Synthesis of Axially Chiral 3,3′‐Disilyl Dicarboxylic Acids by Silalactones

The method is based on the dehydrogenative silalactonization of axially chiral dicarboxylic acid (I) with chlorohydrosilanes, followed by ring opening with Grignard compounds.

Preparation and characterization of optically active polyamides based on 3-phenyl-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino in 1,3-dipropylimidazolium bromide

The exploitation of ionic liquids (IL)s for the preparation and use of non-vinyl macromolecules brings together two of the most stimulating and promising areas of research from recent years. In this study, IL, 1,3-dipropylimidazolium bromide, was examined as a replacement for volatile toxic organic solvents for the direct polycondensation of chiral dicarboxylic acid monomer, 5-[3-phenyl-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino]isophthalic acid (1) with diverse aromatic diamines (2a–2g). The optically active polyamides (PA)s were obtained in 80–98% yield and the inherent viscosities in the range of 0.39–0.69 dLg−1. The higher inherent viscosities and thermal stability were found in this IL compared to analogous compounds in organic solvents under milder reaction conditions. The yields of the PAs were comparable. All the polymers were amorphous and exhibited excellent solubility in many organic solvents. The procedure was found to be an efficient and green technique for the synthesis of the aforementioned PAs. The PAs were characterized by FTIR, specific rotation, 1H NMR, elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry and X-ray diffraction. Open image in new window

Asymmetric Inverse‐Electron‐Demand 1,3‐Dipolar Cycloaddition of C,N‐Cyclic Azomethine Imines: An Umpolung Strategy

Axially chiral dicarboxylic acids (I) exhibit high catalytic activity in the title reaction of dihydroisoquinoline derivatives (II) with vinyl ether (III) to give the cycloadducts exclusively as exo-isomers with excellent enantioselectivities.

ChemInform Abstract: Enantioselective Formal Alkenylations of Imines Catalyzed by Axially Chiral Dicarboxylic Acid Using Vinylogous Aza‐Enamines.

AbstractCompounds (III) and (V) are obtained as mixtures of E‐ and Z‐isomers with the internal E‐isomer predominating except for (Vb).

Axially Chiral Dicarboxylic Acid Catalyzed Formal Alkenylations of Imines

Axially Chiral Dicarboxylic Acid Catalyzed Formal Alkenylations of Imines

Enantioselective Formal Alkenylations of Imines Catalyzed by Axially Chiral Dicarboxylic Acid Using Vinylogous Aza‐Enamines

Enantioselective Formal Alkenylations of Imines Catalyzed by Axially Chiral Dicarboxylic Acid Using Vinylogous Aza‐Enamines

Enantioselective Formal Alkenylations of Imines Catalyzed by Axially Chiral Dicarboxylic Acid Using Vinylogous Aza‐Enamines

In the zone: The use of vinylogous aza-enamaines (hydrazones) as a source of an alkenyl group has been achieved (see scheme). Unmasking of the aza-enamine moiety opens up a novel approach for the preparation of chiral allylic amines bearing an electron-withdrawing alkene moiety functionalized at the electron-deficient β position.

High-Speed Microwave-Promoted Direct Poly-amidation Reactions of Bulky Chiral Dicarboxylic Acide with Different Aromatic Diamines in Imidazolium Types Ionic Liquid as a Reaction Medium

A comparison of ionic liquid (ILs) and volatile organic solvent as a reaction medium under microwave irradiation in the synthesis of novel organosoluble polyamides (PAs) is discussed. High polarities of the ILs make them an efficient substrate for quick heating under microwave irradiation. Direct polyamidation of our synthesized chiral dicarboxylic acid monomer (9), with several aromatic diamines was performed under microwave irradiation in different media, such as IL/triphenyl phosphite (TPP) or TPP, N-methyl-2-pyrrolidinone, pyridine and calcium chloride. The polymerization reactions occurred rapidly under microwave irradiation and produced a series of novel PAs having inherent viscosities of 0.36–0.85 dl/g and high yields. These aromatic PAs had useful levels of thermal stability associated with their relatively medium-high glass-transition temperature (155–168°C), 10% weight-loss temperatures in excess of 385°C and char yields at 800°C in nitrogen higher than 56%. In order to see the efficiency of microwave irradiation conjugated with ILs, this method was compared with polycondensation of this monomer in N-methyl-2-pyrilidone under microwave irradiation and the results are comparable.

ChemInform Abstract: Design of an Axially Chiral Dicarboxylic Acid and Its Application in Syntheses of Optically Active β‐Amino Acids and β‐Amino Phosphonic Acid Derivatives.

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