Primary Amine Thiourea Research Articles

Bifunctional primary amine-thiourea–TfOH (BPAT·TfOH) as a chiral phase-transfer catalyst: the asymmetric synthesis of dihydropyrimidines

An enantioselective Biginelli reaction has been developed by using a bifunctional primary amine-thiourea-TfOH (BPAT·TfOH) as a chiral phase-transfer catalyst and t-BuNH(2)·TFA as an additive in saturated brine at room temperature. The corresponding dihydropyrimidines were obtained in moderate-to-good yields with up to 99% ee under mild conditions. A plausible transition state has been proposed to explain the origin of the activation and the asymmetric induction.

ChemInform Abstract: A Simple Primary Amine Thiourea Catalyzed Highly Enantioselective Conjugate Addition of α,α‐Disubstituted Aldehydes to Maleimides.

AbstractThe approach serves as a powerful tool for the preparation of synthetically and biologically important chiral disubstituted α‐branched succinimides.

ChemInform Abstract: Highly Enantioselective Michael Addition of Aldehydes to Nitroolefins Catalyzed by Primary Amine Thiourea Organocatalysts.

AbstractBifunctional cinchonidine‐derived thiourea catalysts (I), (II) are prepared for the highly enantioselective Michael addition of α‐branched aldehydes towards aromatic nitroolefins.

Chiral primary amine thiourea promoted highly enantioselective Michael reactions of isobutylaldehyde with maleimides

Chiral primary amine thiourea catalysts were first successfully applied to promote Michael addition of isobutyraldehyde to maleimides. A variety of N-aryl and N-aliphatic maleimides provided Michael adducts in excellent yields (up to 98%) and enantioselectivities (up to 99% ee) with 5 mol % catalyst.

Asymmetric Organocatalytic Michael Addition of α,β-Unsaturated Ketone with 1,2,4-Triazole

The Michael addition of α,β-unsaturated ketone with triazole was efficiently catalyzed by the primary amine thiourea catalyst and the desired products were formed in high yields with moderate to excellent enantioselectivities.

ChemInform Abstract: Highly Enantioselective Michael Addition of Isobutyraldehyde to Nitroalkenes.

Abstract The asymmetric catalytic Michael reaction between isobutyraldehyde and nitroalkanes with chiral primary amine thiourea organocatalysts was described. In the presence of 10 mol % of 1-((1R,2R)-2-amino-1,2-diphenylethyl)-3-benzylthiourea, the desired products were achieved in excellent enantioselectivity (up to>99% ee) with up to 98% yield.

A Simple Primary Amine Thiourea Catalyzed Highly Enantioselective Conjugate Addition of α,α‐Disubstituted Aldehydes to Maleimides

Branch point: A simple primary amine thiourea catalyzed highly enantioselective conjugate addition of α,α-disubstituted aldehydes to maleimides has been developed. The biologically useful chiral disubstituted α-branched succinimides are attained with the generation of two contiguous quaternary and/or tertiary stereogenic centers in one step with excellent enantioselectivities and in high yields under mild reaction conditions (see scheme).

Asymmetric Michael Addition of Aromatic Ketones to Nitroolefins Catalyzed by Simple Chiral Bifunctional Primary Amine-Thioureas

Asymmetric Michael Addition of Aromatic Ketones to Nitroolefins Catalyzed by Simple Chiral Bifunctional Primary Amine-Thioureas

Highly enantioselective Michael addition of aldehydes to nitroolefins catalyzed by primary amine thiourea organocatalysts

Asymmetric Michael addition reactions of aldehydes to nitroolefins have been successfully initiated by a series of primary amine thiourea bifunctional catalysts, with high enantioselectivities (90–98% ee) and excellent yields (80–96%). The privileged quinine scaffold was found to be essential to the reaction efficiency and enantioselectivity.

Highly enantioselective Michael addition of isobutyraldehyde to nitroalkenes

The asymmetric catalytic Michael reaction between isobutyraldehyde and nitroalkanes with chiral primary amine thiourea organocatalysts was described. In the presence of 10 mol % of 1-((1 R,2 R)-2-amino-1,2-diphenylethyl)-3-benzylthiourea, the desired products were achieved in excellent enantioselectivity (up to>99% ee) with up to 98% yield.

Enantioselective Michael Addition of Aromatic Ketones to Nitroolefins Catalyzed by Bifunctional Thioureas and Mechanistic Insight

AbstractA highly enantioselective Michael reaction of aromatic ketones with nitroolefins was accomplished in the presence of a chiral bifunctional primary amine–thiourea catalyst and 4‐nitrobenzoic acid as the co‐catalyst; the corresponding adducts were obtained in excellent enantioselectivities (up to 99 % ee) and yields (up to 98 %). The catalytic mechanism of the Michael reaction was confirmed through the ESI‐MS detection of proposed reaction intermediates and the 1H NMR detection of hydrogen bonding between thiourea and the nitroolefins. DFT calculations showed that chiral moieties of the thiourea impacted the yields and enantioselectivities of the adducts remarkably, which corresponds to the observed experimental results.

A highly efficient asymmetric Michael addition of α,α-disubstituted aldehydes to maleimides catalyzed by primary amine thiourea salt

The first highly efficient Michael addition of challenging α,α-disubstituted aldehydes to maleimides catalyzed by a simple bifunctional primary amine thiourea catalyst/benzoic acid system has been successfully developed to generate quaternary carbon centers in high yields (up to 99%) with excellent enantioselectivities (91-99%).

Editorial: Crystal‐Clear View of Chemistry

Editorial: Crystal‐Clear View of Chemistry

One‐Pot Organocatalytic Asymmetric Synthesis of 3‐Nitro‐1,2‐dihydroquinolines by a Dual‐Activation Protocol

Generally, amine-catalyzed enantioselective transformations rely on chiral enamine or unsaturated iminium intermediates. Herein, we report a protocol involving dual activation by an aromatic iminium and hydrogen-bonding. An enantioselective aza-Michael-Henry domino reaction of 2-aminobenzaldehydes with nitroolefins has been developed through this protocol using primary amine thiourea catalysts to provide a variety of 3-nitro-1,2-dihydroquinolines in moderate yields and with up to 90% ee. The mechanism for the catalytic enantioselective reaction was confirmed by ESI mass spectrometric detection of the reaction intermediates. The products formed are substructures found in skeletons of important biological and pharmaceutical molecules.

ChemInform Abstract: Simple Cyclohexanediamine‐Derived Primary Amine Thiourea Catalyzed Highly Enantioselective Conjugate Addition of Nitroalkanes to Enones.

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.

Enantioselective Organocatalytic Conjugate Addition of Aromatic Ketones to Nitrodienes

The organocatalytic asymmetric nitro-Michael addition of aromatic ketones to nitrodiene using various chiral primary amine thioureas was described. In the presence of 30 mol% of N-[(1R,2R)-2-amino-1,2-diphenylethyl]-N′-benzylthiourea, the Michael adducts were obtained in good yields and excellent enantio­selectivity (94-98% ee).

ChemInform Abstract: Highly Enantioselective Michael Addition of Acetone to Nitroolefins Catalyzed by Chiral Bifunctional Primary Amine—Thiourea Catalysts with Acetic Acid.

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.

Asymmetric Iminium Ion Catalysis with a Novel Bifunctional Primary Amine Thiourea: Controlling Adjacent Quaternary and Tertiary Stereocenters

A chiral primary amine thiourea catalyzes the stereoselective addition of oxindoles to α,β-unsaturated aldehydes, generating valuable chiral scaffolds with contiguous quaternary and tertiary stereocenters (see scheme). For the first time, a chiral primary amine thiourea catalyst has been successfully applied for iminium-ion activation.

Simple Cyclohexanediamine-Derived Primary Amine Thiourea Catalyzed Highly Enantioselective Conjugate Addition of Nitroalkanes to Enones

A highly enantioselective conjugate addition of nitroalkanes to enones has been developed. The process is efficiently catalyzed by a simple chiral cyclohexanediamine-derived primary amine thiourea with a broad substrate scope.

Highly enantioselective Michael addition of acetone to nitroolefins catalyzed by chiral bifunctional primary amine-thiourea catalysts with acetic acid

Highly enantioselective Michael reaction of acetone with a variety of nitroolefins catalyzed by N-[(1R,2R)-2-aminocyclohexyl]-N′-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-thiourea (1b) together with acetic acid is described. The Michael addition products were obtained in high yields (76–94%) and up to 96% ee.