Modular Chiral Bisoxalamide–Copper-Catalyzed Asymmetric Oxo-Diels–Alder Reaction: Carbonyl Coordination for High Enantio- and Diastereocontrols

TBHP Mediated C-N Bond Cleavage of Tertiary Amines toward the Synthesis of Oxalamides and α,β-Epoxy Amides

An efficient and convenient method for the synthesis of oxalamides by the reaction of β-ketoamides with tertiary amines and TBHP was developed. A variety of β-ketoamides and tertiary amines substrates were well-tolerated in this transformation. Based on the control experiments, a plausible mechanism for this reaction was proposed that involved the tandem oxidation/amination process. In addition, α,β-epoxy amides could be obtained by adjusting the reaction conditions.

Controllable Synthesis of N- and O-Containing Heterocycles via Formal [3 + 2] and [5 + 2] Cyclizations

The controllable synthesis of spirooxindole-dihydrofurans and spirooxindole-benzazepines was developed through formal [3 + 2] and [5 + 2] cyclization reactions from 2-(2-oxoindolin-3-yl)malononitriles and ortho-aminobenzaldehydes, respectively. A variety of spirooxindole-benzazepines were facilely constructed via a furan ring-open-involved hydride transfer/cyclization process. It is noteworthy that the application of the hydride-transfer-involved [5 + 2] cyclization strategy for construction of spirobenzazepines was unprecedented. In addition, the spiro N- and O-containing heterocycles were highly functionalized by amino, amide, and cyano groups, which were conducive to late-stage functionalization.

A Class of Enantiomerically Pure Bis-oxamide Palladium Complexes: Modular Synthesis via Domino C(sp2)-H Bond Arylation and Photophysical Property

A one-pot, five-step domino reaction was developed for the arylation of bis-oxamides derived from optically pure 1,2-diphenylethylenediamine, leading to the formation of a series of chiral bis-oxalamide palladium(II) complexes bearing tetraaryl-conjugated substituents in good yields. In addition, these palladium(II) complexes exhibited perceptible blue fluorescence under ultraviolet light irradiation.

Chiral oxalamide phosphine (COAP)-Pd-catalyzed enantioselective cascade formal [4 + 1] annulation for enantioenriched 2,3-disubstituted indolines and further DFT study on regio- and stereocontrol

COAP-Pd-catalyzed asymmetric cascade formal [4 + 1] annulation was developed between racemic vinyl benzoxazinones and N-tosylhydrazone sodium salts, affording trans-2,3-disubstituted indolines in good yields with high stereoselectivity.

Copper-Catalyzed Stereoselective [4 + 2] Cycloaddition of β,γ-Unsaturated α-Keto Esters and 2-Vinylpyrroles in Water

An asymmetric [4 + 2] cycloaddition of β,γ-unsaturated α-keto esters with 2-vinylpyrroles in water was developed under the catalysis of a kind of copper complex with a low loading. A series of optically pure 3,4-dihydro-2H-pyran derivatives could be obtained in excellent yields, with high diastereoselectivities and enantioselectivities. The corresponding mechanism was proposed, which was supported by DFT calculations.

Enantioselective Organocopper-Catalyzed Hetero Diels-Alder Reaction through in Situ Oxidation of Ethers into Enol Ethers

We disclose a catalytic method for the enantio- and diastereoselective union of alkyl ethers and heterodienes. We demonstrate that a chiral Cu-BOX complex catalyzes the efficient oxidation of ethers into enol ethers in the presence of trityl acetate. Then, the organocopper promotes stereoselective hetero Diels-Alder reaction between the in situ generated enol ethers and β,γ-unsaturated ketoesters, allowing for rapid access to an array of dihydropyran derivatives possessing three vicinal stereogenic centers.

Chiral oxamide–phosphine–palladium catalyzed highly asymmetric allylic amination: carbonyl assistance for high regio- and enantiocontrols

The chiral oxamide–phosphine (COAP) ligands were developed for the palladium-catalyzed asymmetric allylic amination of vinyl benzoxazinones with alkylamines, affording a series of optically active diamines in good yields with high enantioselectivity.

Chiral-at-Iron Catalyst for Highly Enantioselective and Diastereoselective Hetero-Diels-Alder Reaction

This study demonstrates that chiral-at-iron complexes, in which all coordinated ligands are achiral and the overall chirality the consequence of a stereogenic iron center, are capable of catalyzing asymmetric transformations with very high enantioselectivities. The catalyst is based on a previously reported design (J. Am. Chem. Soc. 2017, 139, 4322), in which iron(II) is surrounded by two configurationally inert achiral bidentate N-(2-pyridyl)-substituted N-heterocyclic carbenes in a C2 -symmetric fashion and complemented by two labile acetonitriles. By replacing mesityl with more bulky 2,6-diisopropylphenyl substituents at the NHC ligands, the steric hindrance at the catalytic site was increased, thereby providing a markedly improved asymmetric induction. The new chiral-at-iron catalyst was applied to the inverse electron demand hetero-Diels-Alder reaction between β,γ-unsaturated α-ketoester and enol ethers provide 3,4-dihydro-2H-pyrans in high yields with excellent diastereoselectivities (up to 99 : 1 dr) and excellent enantioselectivities (up to 98 % ee). Other electron rich dienophiles are also suitable as demonstrated for a reaction with a vinyl azide.

Recent advances in the catalytic synthesis of 3-aminooxindoles: an update

3-Substituted-3-aminooxindoles are versatile scaffolds and these motifs constitute the core structure of number of natural products and biologically active compounds.

Vibrational circular dichroism towards asymmetric catalysis: chiral induction in substrates coordinated with copper(ii) ions

The VCD method was applied for searching the origin of chirality selection in the asymmetric catalysis by Cu(ii) complexes. When 1-phenyl-1,3-butanedionato was coordinated, it was transformed to a twisted chiral form under the steric control.