Leijie Zhou

Cu(I)-Catalyzed Highly Enantioselective [3 + 3] Cycloaddition between Two Different 1,3-Dipoles, Phthalazinium Dicyanomethanides and Iminoester-Derived Azomethine Ylides

The Cu(I)-catalyzed highly enantioselective [3 + 3] cycloaddition between two different 1,3-dipoles, phthalazinium dicyanomethanides and iminoester-derived azomethine ylides, has been achieved under mild reaction conditions, providing novel chiral heterocyclic compounds, 2,3,4,11b-tetrahydro-1H-pyrazino[2,1-a]phthalazine derivatives, in high yields with excellent diastereo- and enantioselectivies (up to 99% yield, 99% ee, >20:1 dr).

Phosphine-Catalyzed [2 + 4] Annulation of Allenoates with Thiazolone-Derived Alkenes: Synthesis of Functionalized 6,7-Dihydro-5H-pyrano[2,3-d]thiazoles

Phosphine-catalyzed [2 + 4] annulation of allenoates with thiazolone-derived alkenes has been achieved under mild conditions, giving biologically important 6,7-dihydro-5H-pyrano[2,3-d]thiazole derivatives in high to excellent yields. With the use of Kwons phosphine as the chiral catalyst, optically active products were obtained in good yields with excellent enantioselectivities.

Phosphine-catalyzed [4 + 2] cycloaddition of unsaturated pyrazolones with allenoates: a concise approach toward spiropyrazolones

A MePPh2-catalyzed [4 + 2] cycloaddition reaction of unsaturated pyrazolones with allenoates was described. The reaction affords the spiropyrazolone derivatives in moderate to excellent yields with moderate to good diastereoselectivities under mild conditions. Using thiourea-based bifunctional phosphines as chiral catalysts, an asymmetric variant of this [4 + 2] cycloaddition reaction has been achieved, giving chiral spiropyrazolone derivatives in moderate to excellent yields with moderate to excellent diastereoselectivities and excellent enantioselectivities (89–95% ee).

Phosphine-Catalyzed Enantioselective [2+4] Cycloaddition to Synthesize Pyrrolidin-2-one Fused Dihydropyrans Using α-Substituted Allenoates as C2 Synthons

A bifunctional phosphine-catalyzed highly enantioselective [2+4] cycloaddition of α-substituted allenoates with (E)-1-benzyl-4-olefinicpyrrolidine-2,3-diones has been achieved, giving pyrrolidin-2-one fused dihydropyran derivatives in moderate to good yields with excellent enantioselectivities (up to 98% ee). This reaction provides a useful catalytic asymmetric access to dihydropyran structural motifs.

Phosphine-catalyzed [3 + 2] cycloaddition of phthalazinium dicyanomethanides with allenoates: highly efficient synthesis of 1,2,3,10b-tetrahydropyrrolo[2,1-a]phthalazine derivatives

The phosphine-catalyzed [3 + 2] cycloaddition between phthalazinium dicyanomethanides and allenoates, has been achieved in dichloromethane at room temperature, providing a broad range of novel heterocyclic compounds, 1,2,3,10b-tetrahydropyrrolo[2,1-a]phthalazine derivatives, as single (Z)-isomers in excellent yields (88–99% yield). All reactions are operationally simple and proceed very fast under mild reaction conditions.

Phosphine-catalyzed asymmetric [3 + 2] annulation of chalcones with allenoates for enantioselective synthesis of functionalized cyclopentenes

Chiral phosphine-catalyzed asymmetric [3 + 2] annulation reaction of various Boc-amino-substituted chalcones with allenoates has been developed, leading to efficient formation of 1,4,5-trisubstituted cyclopentenes with high yields, excellent diastereoselectivities and enantioselectivities (up to 99% ee and up to 98% yield).

Enantioselective Construction of Tetrahydroquinazoline Motifs via Palladium-Catalyzed [4 + 2] Cycloaddition of Vinyl Benzoxazinones with Sulfamate-Derived Cyclic Imines

A palladium-catalyzed enantioselective [4 + 2] cycloaddition reaction of vinyl benzoxazinones with sulfamate-derived cyclic imines is described, affording the tetrahydroquinazolines bearing several functional rings in high yields (up to 99% yield) with good to excellent diastereoselectivities and excellent enantioselectivities (up to 96% ee). This reaction represents the first Pd-catalyzed asymmetric decarboxylative cycloaddition of vinyl benzoxazinones with imines.

Palladium-Catalyzed [5 + 2] Cycloaddition of Vinyloxiranes with Sulfamate-Derived Cyclic Imines To Construct 1,3-Oxazepine Heterocycles

Palladium-catalyzed [5 + 2] cycloaddition of 2-aryl-2-vinyloxiranes with sulfamate-derived cyclic imines is described. The zwitterionic allylpalladium intermediates act as five-membered synthon to react with sulfamate-derived cyclic imines to furnish [5 + 2] cycloaddition, giving 1,3-oxazepine derivatives in moderate to excellent yields with excellent regioselectivities.

Phosphine-Catalyzed [8 + 2]-Annulation of Heptafulvenes with Allenoates and Its Asymmetric Variant: Construction of Bicyclo[5.3.0]decane Scaffold

In this paper, a phosphine-catalyzed [8 + 2]-annulation of heptafulvene with allenoates has been achieved under mild conditions, giving functionalized bicyclo[5.3.0]decane derivatives in moderate to excellent yields. Using chiral phosphine as the catalyst, optically active products were obtained in moderate to high yields with excellent enantioselectivities.

Phosphine-Catalyzed [3 + 2] Annulation of 2-Hydroxy-1,4-naphthaquinones and Allenoate: An Allene–Alkene [3 + 2] Annulation Mechanism Involving Consecutive γ-Addition–Aldol Reaction

A diastereoselective construction of biologically important tetrahydrocyclopenta[ b]naphthalene derivatives has been achieved via a phosphine-catalyzed [3 + 2] annulation of 2-hydroxy-1,4-naphthaquinone derivatives and allenoate. Various tetrahydrocyclopenta[ b]naphthalene derivatives containing contiguous quaternary carbon centers are obtained in good yields with excellent diastereoselectivities. The asymmetric version gave the chiral product in up to 57% ee under catalysis of Kwon chiral phosphine. The reaction undergoes a reaction mechanism involving consecutive γ-addition-aldol reaction.