An N-Linked Bidentate Phosphoramidite Ligand (N-Me-BIPAM) for Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to N-Sulfonylarylaldimines

Nickel-Catalyzed Enantioselective Reductive Arylation and Heteroarylation of Aldimines via an Elementary 1,4-Addition

Nickel catalysts of chiral pyrox ligands promoted enantioselective reductive arylation and heteroarylation of aldimines, using directly (hetero)aryl halides and sulfonates. The catalytic arylation can also be conducted with crude aldimines generated from condensation of aldehydes and azaaryl amines. Mechanistically, density functional theory (DFT) calculations and experiments pointed to an elementary step of 1,4-addition of aryl nickel(I) complexes to N-azaaryl aldimines.

Enantioselective C,P-Palladacycle-Catalyzed Arylation of Imines

Chiral diarylmethylamines are of great interest because of their prevalence in biological and pharmaceutical sciences. Herein, we report a C,P-palladacycle-catalyzed enantioselective synthesis of chiral diarylmethylamines via asymmetric arylation of N-protected imines with arylboronic acids. The C,P-palladacycle showed high reactivity (up to 99% yield) and enantioselectivity (up to 99% ee) toward this arylation, enabling the tolerance of a wide range of functionalities, providing a convenient and efficient access to enantiomerically enriched diarylmethylamines. The absolute configuration of the product was well rationalized by the proposed stereochemical pathway and the catalytical cycle.

Copper-Catalyzed Asymmetric Arylation of N-Heteroaryl Aldimines: Elementary Step of a 1,4-Insertion

Copper complexes of monodentate phosphoramidites efficiently promote asymmetric arylation of N-azaaryl aldimines with arylboroxines. DFT calculations and experiments support an elementary step of 1,4-insertion in the reaction pathway, a step in which an aryl-copper species adds directly across four atoms of C=N-C=N in the N-azaaryl aldimines.

Approach to Chiral 1-Substituted Isoquinolone and 3-Substituted Isoindolin-1-one by Addition-Cyclization Process

An approach to access 1-substituted isoquinolones has been developed through the addition-cyclization of imines with Grignard reagents in the presence of 2,2'-dipyridyl. A number of substituted aromatic magnesium reagents were amenable to this process, and the desired products were obtained with excellent yields and outstanding diastereoselectivities ( dr > 99:1). The utility of this convenient approach is demonstrated by the formal synthesis of ( S)-cryptostyline II. Moreover, N-methylmorpholine (NMM) was found to be an effective additive for the formation of 3-substituted isoindolin-1-ones using one-pot addition-cyclization-deprotection of imine with Grignard reagents.

Ni(ii)-catalyzed asymmetric addition of arylboronic acids to cyclic imines

A Ni(ii)-catalyzed asymmetric addition of arylboronic acids to cyclic imines has been realized using a tropos biphenyl phosphine-oxazoline ligand.

Asymmetric Synthesis of Isoquinoline Alkaloids: 2004-2015

In the past decade, the asymmetric synthesis of chiral nonracemic isoquinoline alkaloids, a family of natural products showing a wide range of structural diversity and biological and pharmaceutical activity, has been based either on continuation or improvement of known traditional methods or on new, recently developed, strategies. Both diastereoselective and enantioselective catalytic methods have been applied. This review describes the stereochemically modified traditional syntheses (the Pictet-Spengler, the Bischler-Napieralski, and the Pomeranz-Fritsch-Bobbitt) along with strategies based on closing of the nitrogen-containing ring B of the isoquinoline core by the formation of bonds between C₁-N₂, N₂-C₃, C₁-N₂/N₂-C₃, and C₁-N₂/C₄-C_4a atoms. Methods involving introduction of substituents at the C1 carbon of isoquinoline core along with syntheses applying various biocatalytic techniques have also been reviewed.

Rhodium-Catalyzed Enantioselective Arylation of Aliphatic Imines

Chiral rhodium(I)-catalyzed highly enantioselective arylation of aliphatic N-sulfonyl aldimines with arylboronic acids has been developed. This transformation is achieved by the use of a rhodium/bis(phosphoramidite) catalyst to give enantiomerically enriched α-branched amines (up to 99 % ee). In addition, this system enables efficient synthesis of (+)-NPS R-568 and Cinacalcet which are calcimimetic agents.

Synthesis of benzofuranyl and indolyl methyl azides by tandem silver-catalyzed cyclization and azidation

A tandem Ag-catalyzed 5-exo-dig cyclization and catalyst free γ-azidation for benzofuranyl/indolyl methyl azides is presented. The adducts are further transformed to useful triazole-, tetrazole-, amide-, amine-, and pyrido-derivatives.

Cationic Iridium/S-Me-BIPAM-Catalyzed Direct Asymmetric Intermolecular Hydroarylation of Bicycloalkenes

Highly enantioselective cationic iridium-catalyzed hydroarylation of bicycloalkenes, by carbonyl-directed C-H bond cleavage, was accomplished using a newly synthesized sulfur-linked bis(phosphoramidite) ligand (S-Me-BIPAM). The reaction provides alkylated acetophenone or benzamide derivatives in moderate to excellent yields and good to excellent enantioselectivities. Notably, the hydroarylation reaction of 2-norbornene with N,N-dialkylbenzamide proceeds with excellent enantioselectivity (up to 99% ee) and high selectivity for the mono-ortho-alkylation product.

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.

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.

Ru/Me-BIPAM-catalyzed asymmetric addition of arylboronic acids to aliphatic aldehydes and α-ketoesters

A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(aryl)methanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM) achieved excellent enantioselectivities.