Enantioselective Aminolysis Research Articles

Asymmetric Catalytic Syntheses of Pharmaceutically Important β‐Amino‐α‐Hydroxyl Esters by Enantioselective Aminolysis of Methyl Phenylglycidate

AbstractChiral macrocyclic CrIII salen complexes have been synthesized, characterized, and used as catalysts in the asymmetric aminolysis of aromatic ester epoxides with various anilines to prepare the β‐amino‐α‐hydroxyl esters in very good yield (up to 95 %) along with high diastereo‐ and enantioselectivity (dr>99/1, ee up to 96 %) under the optimized condition particularly with CrIII complex 4, which was effectively recycled four times.

Synthesis of Chiral Vicinal Diamines by Silver(I)‐Catalyzed Enantioselective Aminolysis of N‐Tosylaziridines

AbstractThe kinetic resolution of 2‐aryl‐N‐tosylaziridines and the asymmetric desymmetrization of meso‐N‐tosylaziridines by ring openings with various primary and secondary anilines, and aliphatic amines as nucleophile have been realized by using a single silver(I)/chiral diphosphine complex as catalyst for the first time. The simple starting materials, broad scope, and easy scalability render this protocol a practical way to chiral vicinal diamine derivatives.

Synthesis of Chiral Vicinal Diamines by Silver(I)-Catalyzed Enantioselective Aminolysis of N-Tosylaziridines.

The kinetic resolution of 2-aryl-N-tosylaziridines and the asymmetric desymmetrization of meso-N-tosylaziridines by ring openings with various primary and secondary anilines, and aliphatic amines as nucleophile have been realized by using a single silver(I)/chiral diphosphine complex as catalyst for the first time. The simple starting materials, broad scope, and easy scalability render this protocol a practical way to chiral vicinal diamine derivatives.

ChemInform Abstract: Green Regio‐ and Enantioselective Aminolysis Catalyzed by Graphite and Graphene Oxide under Solvent‐Free Conditions.

The ring-opening reactions of epoxides with amines were efficiently and regioselectively catalyzed by high-surface-area graphite and graphene oxide under metal-free and solvent-free conditions. For epoxides without aryl groups, catalytic activity was observed only for graphene oxide, and hence, the activity must have been due to its acidic groups. For styrene oxide, instead, graphite and graphene oxide exhibited rather similar catalytic activities, and hence, the activity was mainly due to activation of the electrophilic epoxide by π-stacking interactions with the graphitic π system. The described aminolysis procedure is green and cheap because the catalyst can be recovered and recycled without loss of efficiency. Moreover, these heterogeneous catalysts exert high stereoselective control in the presence of nonracemic epoxides and provide chiral β-amino alcohols with enantiomeric excess values up to 99 %.

Green Regio‐ and Enantioselective Aminolysis Catalyzed by Graphite and Graphene Oxide under Solvent‐Free Conditions

AbstractThe ring‐opening reactions of epoxides with amines were efficiently and regioselectively catalyzed by high‐surface‐area graphite and graphene oxide under metal‐free and solvent‐free conditions. For epoxides without aryl groups, catalytic activity was observed only for graphene oxide, and hence, the activity must have been due to its acidic groups. For styrene oxide, instead, graphite and graphene oxide exhibited rather similar catalytic activities, and hence, the activity was mainly due to activation of the electrophilic epoxide by π‐stacking interactions with the graphitic π system. The described aminolysis procedure is green and cheap because the catalyst can be recovered and recycled without loss of efficiency. Moreover, these heterogeneous catalysts exert high stereoselective control in the presence of nonracemic epoxides and provide chiral β‐amino alcohols with enantiomeric excess values up to 99 %.

Rational Design of Amine Nucleophiles for Dynamic Kinetic Resolution of Azlactones Leading to Highly Enantioselective Synthesis of Bisamides

AbstractThe first catalytic asymmetric aminolysis of azlactones was achieved, enabling the highly enantioselective dynamic kinetic resolution of azlactones. This was demonstrated to be an efficient method for synthesizing optically pure bisamides in high yield with excellent enantioselectivity (up to 99 % yield, 99 % ee). The rational design of the amine nucleophile bearing both a sterically bulky group and an activating group was shown to be a key factor in attaining excellent enantioselectivity in the catalytic asymmetric aminolysis of azlactones. This approach not only provides easy access to biologically important enantiopure bisamides, but also enables the dynamic kinetic resolution of azlactones by using a strategy of enantioselective aminolysis, which was previously unknown in this research field.

Chiral Co(iii)–salen complex supported over highly ordered functionalized mesoporous silica for enantioselective aminolysis of racemic epoxides

New mesoporous chiral Co(iii)-catalyst has been synthesed and used in the synthesis of chiral β-amino alcohols with excellent yield and enantioselectivity (ee > 99%) under neat conditions at RT.

A new recyclable functionalized mesoporous SBA-15 catalyst grafted with chiral Fe(iii) sites for the enantioselective aminolysis of racemic epoxides under solvent free conditions

A mesoporous SBA-15 supported chiral Fe(iii)-catalyst was prepared and used for the synthesis of chiral β-amino alcohols with very good yields and enantioselectivities (ee upto 98%) under neat conditions at RT.

Gadolinium-Catalyzed Regio- and Enantioselective Aminolysis of Aromatic trans-2,3-Epoxy Sulfonamides.

The first enantioselective aminolysis of aromatic trans-2,3-epoxy sulfonamides has been accomplished, which was efficiently catalyzed by a Gd-N,N'-dioxide complex. Under the directing effect of the sulfonamide moiety the ring-opening reaction proceeded selectively at the C-3 position in a highly enantioselective manner furnishing various Ts- and SES-protected 3-amino-3-phenylpropan-2-olamines as products.

Gadolinium‐Catalyzed Regio‐ and Enantioselective Aminolysis of Aromatic trans‐2,3‐Epoxy Sulfonamides

AbstractThe first enantioselective aminolysis of aromatic trans‐2,3‐epoxy sulfonamides has been accomplished, which was efficiently catalyzed by a Gd‐N,N′‐dioxide complex. Under the directing effect of the sulfonamide moiety the ring‐opening reaction proceeded selectively at the C‐3 position in a highly enantioselective manner furnishing various Ts‐ and SES‐protected 3‐amino‐3‐phenylpropan‐2‐olamines as products.

ChemInform Abstract: Tungsten‐Catalyzed Regio‐ and Enantioselective Aminolysis of trans‐2,3‐Epoxy Alcohols: An Entry to Virtually Enantiopure Amino Alcohols.

AbstractThe first catalytic enantioselective aminolysis of trans‐2,3‐epoxy alcohols is accomplished in the presence of a tungsten/bis(hydroxamic acid) catalytic system.

Nickel-catalyzed regio- and enantioselective aminolysis of 3,4-epoxy alcohols.

The first catalytic regio- and enantioselective aminolysis of 3,4-epoxy alcohols has been accomplished. Under the catalysis of Ni(ClO4)2·6H2O, the C4 selective ring opening of various 3,4-epoxy alcohols proceeded in a stereospecific manner with high regioselectivities. Furthermore, with the Ni-BINAM catalytic system the enantioselective ring opening of 3,4-epoxy alcohols furnished various γ-hydroxy-δ-amino alcohols as products with complete regiocontrol and high enantioselectivities (up to 94% ee).

Tungsten-catalyzed regio- and enantioselective aminolysis of trans-2,3-epoxy alcohols: an entry to virtually enantiopure amino alcohols.

The first catalytic enantioselective aminolysis of trans-2,3-epoxy alcohols has been accomplished. This stereospecific ring-opening process was efficiently promoted by a tungsten/bis(hydroxamic acid) catalytic system, furnishing various anti-3-amino-1,2-diols with excellent regiocontrol and high enantioselectivities (up to 95% ee). Moreover, virtually enantiopure 3-amino-1,2-diols could be obtained by the sequential combination of two reactions that both involve the use of a chiral catalyst.

Tungsten‐Catalyzed Regio‐ and Enantioselective Aminolysis of trans‐2,3‐Epoxy Alcohols: An Entry to Virtually Enantiopure Amino Alcohols

AbstractThe first catalytic enantioselective aminolysis of trans‐2,3‐epoxy alcohols has been accomplished. This stereospecific ring‐opening process was efficiently promoted by a tungsten/bis(hydroxamic acid) catalytic system, furnishing various anti‐3‐amino‐1,2‐diols with excellent regiocontrol and high enantioselectivities (up to 95 % ee). Moreover, virtually enantiopure 3‐amino‐1,2‐diols could be obtained by the sequential combination of two reactions that both involve the use of a chiral catalyst.

ChemInform Abstract: Enzymatic Synthesis of Amides with Two Chiral Centres.

Candida cylindracea lipase and subtilisin protease were utilised in the enantioselective aminolysis of ethyl (±)-2-chloropropionate with racemic amines.

Samarium Iodides: Catalysts for the Formation of Carbon-Nitrogen Bonds

Lanthanide iodides offer great reactive scope as Lewis acid catalysts. Samarium diiodide allows a wide range of carbon-carbon bond-forming reactions, such as Mukaiyama aldol, Diels-Alder, or tandem Mukaiyama Michael aldol reactions. Moreover, lanthanide iodides exhibit high catalytic activities for carbon-nitrogen bond formations which are reviewed here. Highly enantio-enriched amino alcohol and amino acid building blocks are obtained thanks to a new family of enantioselective catalysts developed in our laboratory, iodolanthanide binaphtholates. 1 Introduction 2 Samarium Diiodide Catalyzed Reactions with Formation or Cleavage of Carbon-Nitrogen Bonds 2.1 Ring Opening of Epoxides with Nitrogen Nucleophiles 2.2 Aza-Michael Reactions 2.3 Transformation of N-Acyloxazolidinones into Esters 3 Enantioselective Formation of Carbon-Nitrogen Bonds with Lanthanide Iodides 3.1 Preparation of Chiral Lanthanide Iodides and Enantioselective Catalysis of Carbon-Carbon Bond Forming Reactions 3.2 Enantioselective Aminolysis of Epoxides 3.3 Enantioselective Aza-Michael Reactions 4 Conclusions.

Practical, Highly Enantioselective Chemoenzymatic One-Pot Synthesis of Short-Chain Aliphatic β-Amino Acid Esters

A practical, highly enantioselective method for the synthesis of short-chain aliphatic beta-amino acid esters was developed starting from prochiral and easily accessible Substrates. This chemoenzymatic approach is based oil a nonenzymatic aza-Michael addition of benzylamine to enoates and subsequent lipase-catalyzed resolution via enantioselective aminolysis. The two reactions are carried out as a one-pot synthesis under solvent free-conditions affording the beta-amino esters in satisfying to good yields and with excellent enantioselectivities of up to 99% ee.

Immobilized lipase YlLip2-catalyzed resolution of (±)α-phenylethyl amine in a medium with organic cosolvent

In this paper, we studied the enantioselective aminolysis activity of an immobilized extracellular lipase LIP2 (YlLip2) from Yarrowia lipolytica by catalyzing enantioselective acylation of (±)α-phenylethyl amine with acetic ester in a medium containing cosolvent. The reaction parameters including cosolvent concentration, reaction temperature, amount of the immobilized lipase and the reaction time were optimized. When the reaction was carried out in hexane with the presence of 3% DMSO and six pieces of immobilized lipase at 45 °C for 6 days, the enantiomeric excess of product ( e.e.p) markedly increased from 0.35 (in neat hexane) to 0.96 and the enantiomeric ratio ( E) improved from 2.5 (in neat hexane) to 190. The immobilized lipase could be reused at least five consecutive batches at high E (≈190).

Indium—Bipyridine Catalyzed, Enantioselective Aminolysis of meso‐Epoxides.

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Enantioselective synthesis of heterocyclic β-aminoalcohols catalysed by a samarium iodo binaphtholate

Enantioselective aminolysis of meso-epoxides including a heterocycle catalysed by a samarium iodo binaphtholate has been studied. New β-amino alcohols have been isolated with enantiomeric excesses up to 70%.