Chiral Amino Sulfonamide Research Articles

Catalytic Asymmetric Ring-Opening of σ-Symmetric Cyclic Carbonates with Chiral Amino Sulfonamide Catalysts

Enantioselective ring-opening of σ-symmetric six-membered cyclic carbonates with benzyl alcohol catalyzed by 20 mol% of chiral amino sulfonamide catalysts afforded chiral acyclic carbonates in up to 79% ee.

ChemInform Abstract: Design and Synthesis of a Biphenyl‐Based Chiral Amino Sulfonamide with High Catalytic Performance in Mannich Reactions.

Abstract A biphenyl-based amino sulfonamide was designed to improve the intrinsic low catalytic activity of amine organocatalysts. The newly synthesized amino sulfonamide catalyst promoted the Mannich reaction in a highly enantioselective fashion and a remarkable catalyst turnover number was achieved.

Design and synthesis of a biphenyl-based chiral amino sulfonamide with high catalytic performance in Mannich reactions

A biphenyl-based amino sulfonamide was designed to improve the intrinsic low catalytic activity of amine organocatalysts. The newly synthesized amino sulfonamide catalyst promoted the Mannich reaction in a highly enantioselective fashion and a remarkable catalyst turnover number was achieved.

The direct syn-aldol and anti-Mannich reactions catalyzed by axially chiral amino sulfonamide and contrasts with proline catalysis: Insight from a computational study

Quantum mechanical calculations have been performed to study the stereoselectivities in the direct aldol and Mannich reactions involving special electrophiles such as glyoxylate, glyoxamide and sterically more hindered ketimine. The opposite diastereoselectivities in the axially chiral amino sulfonamide and proline-catalyzed aldol and Mannich reactions have been well reproduced by the density functional theory methods at the BH and HLYP/6-31G** computational level. The origin of the unusual selectivities for the axially chiral amino sulfonamide catalysis can be ascribed to the remoter distance between the bifunctional amino and acid groups in the catalysts in comparison with the traditional proline catalysis.

Density Functional Study of Organocatalytic Cross-Aldol Reactions between Two Aliphatic Aldehydes: Insight into Their Functional Differentiation and Origins of Chemo- and Stereoselectivities

The chemo-, diastereo-, and enantioselectivities in proline and axially chiral amino sulfonamide-catalyzed direct aldol reactions between two enolizable aldehydes with different electronic nature have been studied with the aid of density functional theory (DFT) method. The potential energy profiles for the enamine formation between each aliphatic aldehyde and the catalyst confirm that two subject catalysts can successfully differentiate between 3-methylbutanal as an enamine component and α-chloroaldehydes as a carbonyl component. Transition states associated with the stereochemistry-determining C-C bond-forming step with the enamine intermediate addition to the aldehyde acceptor for proline and chiral amino sulfonamide-promoted aldol reactions are reported. DFT calculations not only provide a good explanation for the formation of the sole cross-aldol product between two aliphatic aldehydes both bearing α-methylene protons but also well reproduce the opposite syn vs anti diastereoselectivities in the chiral amino sulfonamide and proline-catalyzed aldol reactions.

One-pot cross double-Mannich reaction of acetaldehyde catalyzed by a binaphthyl-based amino sulfonamide

A one-pot cross double-Mannich reaction of acetaldehyde was developed, and densely functionalized 1,3-diamines were obtained as a single stereoisomer by use of axially chiral amino sulfonamide (S)-1 as catalyst. Using this catalyst, the one-pot Mannich reaction-aminoxylation was also realized.

Stereocontrolled Synthesis of Vicinal Diamines by Organocatalytic Asymmetric Mannich Reaction of N-Protected Aminoacetaldehydes: Formal Synthesis of (−)-Agelastatin A

The 1,2-diamine (vicinal diamine) motif is present in a number of natural products with interesting biological activity and in many chiral molecular catalysts. The efficient and stereocontrolled synthesis of enantioenriched vicinal diamines is still a challenge to modern chemical methodology. We report here both syn- and anti-selective asymmetric direct Mannich reactions of N-protected aminoacetaldehydes with N-Boc-protected imines catalyzed by proline and the axially chiral amino sulfonamide (S)-3. This organocatalytic process represents the first example of a Mannich reaction using Z- or Boc-protected aminoacetaldehyde as a new entry of α-nitrogen functionalized aldehyde nucleophile in enamine catalysis. The obtained optically active vicinal diamines are useful chiral synthons as exemplified by the formal synthesis of (-)-agelastatin A.

ChemInform Abstract: syn‐Selective Asymmetric Cross‐Aldol Reactions Between Aldehydes and Glyoxylic Acid Derivatives Catalyzed by an Axially Chiral Amino Sulfonamide.

AbstractThe cross‐aldol products (III), (V) and (VII) are highly functionalized and readily converted to synthetically useful and important chiral building blocks such as γ‐lactone (VIII) and γ‐lactam (X).

Molecular recognition of ketomalonates by asymmetric aldol reaction of aldehydes with secondary-amine organocatalysts

A diastereo- and enantioselective aldol reaction between aldehydes and a synthetically useful ketomalonate 1c as a hydrated form was developed, and either anti- or syn-aldol adducts having a chiral tetrasubstituted carbon center were obtained in high enantioselectivities by use of a tetrazole analogue of L-proline (S)-2 or an axially chiral amino sulfonamide (S)-3 as catalyst.

Efficient Organocatalytic Cross-Aldol Reaction between Aliphatic Aldehydes through Their Functional Differentiation

A chemo- and stereoselective asymmetric direct cross-aldol reaction between aliphatic aldehydes and α-chloroaldehydes has been developed as a method for the formation of the sole cross-aldol adduct with both enantio- and diastereocontrol, and either anti- or syn-aldol adducts were obtained in good to excellent stereoselectivities by use of proline or a novel axially chiral amino sulfonamide as catalyst.

Syn-Selective asymmetric cross-aldol reactions between aldehydes and glyoxylic acid derivatives catalyzed by an axially chiral amino sulfonamide

syn-Selective asymmetric cross-aldol reactions of aldehydes with tert-butyl glyoxylate and glyoxamide were realized by the use of an axially chiral amino sulfonamide (S)-1. The cross-aldol products obtained are densely functionalized and readily converted to synthetically useful and important chiral building blocks such as γ-lactone and γ-lactam.

ChemInform Abstract: A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric anti‐Selective Mannich Reactions and syn‐Selective Cross‐Aldol Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Theoretical studies of stereoselectivities in the direct anti-Mannich and syn-aldol reactions catalyzed by axially chiral amino sulfonamide

The origins of the stereoselectivities in the axially chiral amino sulfonamide-catalyzed direct anti-Mannich and syn-aldol reactions have been studied with the aid of density functional theory method. Transition states of the stereochemistry-determining C–C bond-forming step with the enamine intermediate addition to the imine or aldehyde for the subject Mannich and aldol reactions are reported. BH and HLYP/6-31G** calculations provide a good explanation for the diastereoselectivities in the chiral amino sulfonamide-catalyzed anti-Mannich and syn-aldol reactions. Calculated and observed diastereomeric ratio and enantiomeric excess values are in good agreement.

A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric anti‐Selective Mannich Reactions and syn‐Selective Cross‐Aldol Reactions

A direct asymmetric Mannich reaction using a novel axially chiral amino sulfonamide (S)-3 that is highly anti- and enantioselective has been developed. For instance, in the presence of a catalytic amount of (S)-3, the reactions between aldehydes and alpha-imino esters proceeded smoothly to give anti Mannich products with a significantly higher anti/syn ratio and enantioselectivity than previously possible. By utilizing N-Boc-protected aromatic imines instead of alpha-imino esters, the synthetically useful Boc protecting group and various aromatic or heteroaromatic substituents were installed into the anti Mannich products and consequently the substrate scope of the anti-selective Mannich reaction and the synthetic utility of the anti Mannich products have been expanded. The axially chiral amino sulfonamide (S)-3 has also been successfully applied to asymmetric direct cross-aldol reaction between two different aldehydes. The catalyst (S)-3 has the advantage of giving mainly syn products, whereas proline shows the opposite anti selectivity.

ChemInform Abstract: A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric Mannich Reactions of N‐Boc‐Protected Imines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Water-soluble chiral aminosulfonamides as ligands for ruthenium(II)-catalyzed asymmetric transfer hydrogenation

New water-soluble chiral aminosulfonamides were synthesized from (R,R)-1,2-diphenylethylenediamine. The ruthenium catalysts prepared from chiral aminosulfonamide ligands with [RuCl2(p-cymene)]2 were used in the asymmetric transfer hydrogenation of prochiral ketones in water with excellent conversion rates and enantioselectivities without adding any surfactants. The catalysts could be easily recovered and reused several times without loss of enantioselectivity and activity.

A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric Mannich Reactions of N‐Boc‐Protected Imines

The moderate nucleophilicity of the axially chiral amino sulfonamide (S)-1 suppresses the problematic side reactions, including aldol reactions, in the asymmetric Mannich reaction of N-Boc-protected imines with aldehydes. The corresponding adducts are obtained in good yield and excellent stereoselectivity (see scheme; Boc = tert-butoxycarbonyl, Tf = trifluoromethanesulfonyl).

A Designer Axially Chiral Amino Sulfonamide as an Efficient Organocatalyst for Direct Asymmetric Mannich Reactions of N‐Boc‐Protected Imines

AbstractDie mäßige Nucleophilie des axialchiralen Aminosulfonamids (S)‐1 unterdrückt störende Nebenreaktionen, darunter Aldolreaktionen, bei der asymmetrischen Mannich‐Reaktion zwischen N‐Boc‐geschützten Iminen und Aldehyden. Die Addukte entstehen in guten Ausbeuten und mit ausgezeichneter Stereoselektivität (siehe Schema; Boc=tert‐Butoxycarbonyl, Tf=Trifluormethansulfonyl).magnified image

ChemInform Abstract: Direct Asymmetric Aminoxylation Reaction Catalyzed by a Binaphthyl‐Based Chiral Amino Sulfonamide with High Catalytic Performance.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Direct asymmetric aminoxylation reaction catalyzed by a binaphthyl-based chiral amino sulfonamide with high catalytic performance

A binaphthyl-based amino sulfonamide ( S)-2 was applied to the direct asymmetric aminoxylation of aldehydes with nitrosobenzene. The reaction catalyzed by ( S)-2 proceeded smoothly to give the aminoxylated product in good yield with excellent enantioselectivity. This method represents a rare example of the highly enantioselective aminoxylation by a non-proline type catalyst with high catalytic performance.