Catalytic and Enantioselective α-Functionalization of Oxindoles Through Oxidative Reactions with Naphthoquinones

Asymmetric Reaction of p-Quinone Diimide: Organocatalyzed Michael Addition of α-Cyanoacetates

Hitherto unknown catalytic enantioselective transformation of p-quinone diimides is achieved using chiral bifunctional organic molecules. Bifunctional thiourea compounds catalyze the Michael addition of cyanoacetates with excellent yields and enantioselectivities. The initially formed Michael adducts undergo cyclization to yield functionally rich, fused cyclic imidines bearing a quaternary benzylic chiral center. Density functional theory calculations of the competing transition states (TSs) were carried out to explain the observed stereochemical outcome.

Organocatalytic Diversity-Oriented Asymmetric Synthesis of Structurally and Stereochemically Complex Heterocycles

An asymmetric organocatalytic direct arylation approach to construct arylated quaternary stereogenic centers with a catalyst loading of 1 mol % is reported. The formation of the hemiketal moiety in stabilizing the hydroquinone intermediate proves to be important in leading to hydroquinone products instead of oxidation quinone products obtained in previously reported methods. A series of structurally and stereochemically complex heterocyclic frameworks are obtained, including spiro-, dispiro-, fused, and bridged heterocycles.

Catalytic asymmetric reactions and synthesis of quinones

Organo- and metal–ligand catalysed asymmetric reactions of quinones lead to complex enantiopure compounds including quinones.

Organocatalytic asymmetric formal arylation of benzofuran-2(3H)-ones with cooperative visible light photocatalysis

An asymmetric arylation of benzofuran-2(3H)-ones with 1-naphthols has been developed through a cooperative visible light photocatalysis with asymmetric hydrogen-bond catalysis.

Highly enantioselective [3+2] coupling of cyclic enamides with quinone monoimines promoted by a chiral phosphoric acid

A chiral phosphoric acid promoted [3+2] coupling of cyclic enamides with quinone monoimines provided highly enantioenriched polycyclic 2,3-dihydrobenzofurans.

An enantioselective cascade reaction between α,β-unsaturated aldehydes and malonic half-thioesters: a rapid access to chiral δ-lactones

We disclose a novel efficient enantioselective organocatalytic cascade reaction for the preparation of δ-lactones in good to excellent yields (69-93%) and with high to excellent enantioselectivities (88-96% ee).

Bi(OTf)3-catalyzed C–H bond functionalization of azaarenes for the facile access to oxindoles featuring quaternary carbon centers

Bi(OTf)₃-catalyzed sp³ C–H functionalization of 2-alkyl azaarenes to isatylidene malononitriles has been achieved to give oxindoles containing an all-carbon quaternary center.

Organocatalytic asymmetric Michael addition of 3-substituted oxindoles to α,β-unsaturated acyl phosphonates for the synthesis of 3,3′-disubstituted oxindoles with chiral squaramides

The first Michael addition of 3-monosubstituted oxindoles to α,β-unsaturated acyl phosphonates is investigated to give 3,3′-disubstituted oxindoles with excellent results.

Organocatalytic enantioselective formal arylation of azlactones using quinones as the aromatic partner

Catalytic enantioselective formal arylation of azlactones using quinones as the aromatic partner was developed.

Organocatalytic asymmetric Michael addition of unprotected 3-substituted oxindoles to 1,4-naphthoquinone

We reported the first example of organocatalytic Michael addition of unprotected 3-prochiral oxindoles 1 to 1,4-naphthoquinone. Quinidine derivative (DHQD)₂PYR was found to be able to catalyze this reaction in up to 83% ee, with moderate to excellent yields. This method could be used for the synthesis of enantioenriched 3,3-diaryloxindoles, and the catalytic synthesis of which was unprecedented.