Direct Asymmetric Three-Component Mannich Reaction Research Articles

Direct Asymmetric Three-Component Mannich Reaction Catalyzed by Chiral Counteranion-Assisted Silver

Direct asymmetric three-component Mannich reaction involving simple ketones (such as cyclohexanone, acetone, and acetophenone) as donors and catalyzing by silver tartaric acid-derived phosphate was realized to afford a series of optically active β-amino-ketone derivatives in high yields (up to 96%) and good-to-high enantioselectivities (up to 97%) with moderate-to-good diastereoselectivities. This is the first example of direct catalytic asymmetric three-component Mannich reaction via a chiral counteranion-directed strategy.

Three-Component Asymmetric Mannich Reaction Catalyzed by a Lewis Acid with Rhodium-Centered Chirality.

A highly efficient direct asymmetric three-component Mannich reaction of an N-acylpyrazole, an aldehyde and a primary or secondary amine, was enabled by a rhodium-based Lewis-acid catalyst with metal-centered chirality. Excellent enantioselectivities were achieved for a variety of substrates at a typical catalyst loading of merely 0.5 mol % (23 examples, up to 98 % ee).

Efficient catalysts for asymmetric Mannich reactions

Efficient chiral catalysts for direct asymmetric three-component Mannich reactions of ketones, aldehydes and an amine (p-anisidine) have been developed. The corresponding β-amino carbonyl compounds (Mannich adducts) were obtained in good chemical yields and excellent enantio- and diastereoselectivities. The reaction conditions have been optimized by invoking ultrasonication and the influence of some structural moieties of the catalysts on the chemical yield and stereoselectivity of the Mannich products has been evaluated.

Direct asymmetric three-component Mannich reactions catalyzed by a siloxy serine organocatalyst in water

A siloxy- l-serine organocatalyst has been developed to catalyze the asymmetric three-component Mannich reactions in the presence of water via a biphasic system, furnishing the Mannich products in good yields and high enantioselectivities.

Highly Enantioselective Synthesis of 1,2‐Amino Alcohol Derivatives via Proline‐Catalyzed Mannich Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Highly Enantioselective Synthesis of 1,2-Amino Alcohol Derivatives via Proline-Catalyzed Mannich Reaction

Here we report a new catalytic asymmetric synthesis of oxazolidin-2-ones 4 and Cbz-protected 1,2-amino alcohols 5. Our sequence is based on the chemistry of previously unknown 5-acyloxy-oxazolidin-2-ones, which are obtained via proline-catalyzed direct asymmetric three-component Mannich reaction and Baeyer-Villiger oxidation.

The proline-catalyzed direct asymmetric three-component Mannich reaction: scope, optimization, and application to the highly enantioselective synthesis of 1,2-amino alcohols.

We have developed proline-catalyzed direct asymmetric three-component Mannich reactions of ketones, aldehydes, and amines. Several of the studied reactions provide beta-amino carbonyl compounds (Mannich products) in excellent enantio-, diastereo-, regio-, and chemoselectivities. The scope of each of the three components and the influence of the catalyst structure on the reaction are described. Reaction conditions have been optimized, and the mechanism and source of asymmetric induction are discussed. We further present application of our reaction to the highly enantioselective synthesis of 1,2-amino alcohols.