Catalytic Enantioselective Allylation of Ketoimines

Pd(ii)-catalyzed asymmetric addition of arylboronic acids to cyclic N-sulfonyl ketimine esters and a DFT study of its mechanism

A highly efficient palladium-catalyzed asymmetric arylation of cyclic ketimine esters is developed, which provides the desired product in up to 99% yield with up to 99% ee. The mechanism of enantioselection is studied using DFT calculation.

Rhodium-catalyzed asymmetric addition of arylboronic acids to cyclic N-sulfonyl ketimines towards the synthesis of α,α-diaryl-α-amino acid derivatives

Rhodium/chiral diene complex-catalyzed asymmetric addition of arylboronic acids to cyclic ketimines having an ester group proceeded to give the corresponding α-amino acid derivatives in high yields with high enantioselectivity.

Tertiary α-diarylmethylamines derived from diarylketimines and organomagnesium reagents

Organomagnesium reagents enable swift and versatile derivatisation of diarylimines to the corresponding α-substituted diarylmethylamines in excellent yields, through fast and clean reactions.

Copper-catalyzed asymmetric allylation of chiral N-tert-butanesulfinyl imines: dual stereocontrol with nearly perfect diastereoselectivity

Copper-catalyzed asymmetric allylation of chiral N-tert-butanesulfinyl imines has been described.

Practical catalytic method for synthesis of sterically hindered anilines

Synthesis of sterically hindered 1° and 2° anilines from arylboronic esters is accomplished using air-stable and commercially available catalyst precursors.

Copper-catalysed cross-coupling: an untapped potential

Copper is emerging as a viable catalytic metal for cross-coupling reactions to construct carbon–carbon (C–C) bonds.

The isomerization of allylrhodium intermediates in the rhodium-catalyzed nucleophilic allylation of cyclic imines

Allylrhodium species generated from potassium allyltrifluoroborates can undergo isomerization by 1,4-rhodium(I) migration to give more complex isomers, which then react with cyclic imines to provide products with up to three new stereochemical elements. High enantioselectivities are obtained using chiral diene-rhodium complexes.

Catalytic asymmetric allylation of carbonyl compounds and imines with allylic boronates

Enantioselective allylation is a highly used organic reaction to prepare chiral homoallylic alcohols and amines, which serve as important building blocks in the synthesis of a variety of natural products and pharmaceuticals.

Stereoselective allylboration of imines and indoles under mild conditions. An in situ E/Z isomerization of imines by allylboroxines

Direct allylboration of various acyclic and cyclic aldimine, ketimine and indole substrates was performed using allylboronic acids.

Stereoselective formation of amines by nucleophilic addition to azomethine derivatives

This chapter describes state-of-the-art methods to prepare α-chiral amines by the addition of nonstabilized nucleophiles to imine derivatives. The first part of the chapter illustrates the most effective diastereoselective addition reaction (substrate controlled and chiral auxiliary based methods) whereas the second part focuses on catalytic asymmetric methods.

Simple organic molecules as catalysts for enantioselective synthesis of amines and alcohols

The discovery of catalysts that can be used to synthesize complex organic compounds by enantioselective transformations is central to advances in the life sciences; for this reason, many chemists aim to discover catalysts that allow for preparation of chiral molecules as predominantly one mirror-image isomer. The ideal catalyst should not contain precious elements and should bring reactions to completion in a few hours through operationally simple procedures. Here we introduce a set of small organic molecules that can catalyse reactions of unsaturated organoboron reagents with imines and carbonyls; the products of the reactions are enantiomerically pure amines and alcohols, which might serve as intermediates in the preparation of biologically active molecules. A distinguishing feature of this catalyst class is the presence of a 'key' proton embedded within their structure. Catalysts are derived from the abundant amino acid valine and are prepared in large quantities in four steps with inexpensive reagents. Reactions are scalable, do not demand stringent conditions, and can be performed with as little as 0.25 mole per cent catalyst in less than six hours at room temperature to generate products in more than 85 per cent yield and ≥97:3 enantiomeric ratio. The efficiency, selectivity and operational simplicity of the transformations and the range of boron-based reagents are expected to render this advance important for future progress in syntheses of amines and alcohols, which are useful in chemistry, biology and medicine.

Facile preparation of allylzinc species from allylboronates and zinc amide via a boron-to-zinc exchange process and their reactions with carbonyl compounds, imines and hydrazones

Facile formation of allylzinc species from allylboronate and zinc amide was discovered. The boron-to-zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, which were successfully employed in catalytic allylation reactions with electrophiles. Asymmetric catalysis using a chiral zinc amide is also reported.