Zhanhu Sun

Chiral phosphines in nucleophilic organocatalysis

Summary This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita–Baylis–Hillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and acylations of alcohols.

Enantioselective Synthesis of Spirobarbiturate-Cyclohexenes through Phosphine-Catalyzed Asymmetric [4 + 2] Annulation of Barbiturate-Derived Alkenes with Allenoates

An enantioselective synthesis of pharmaceutically important spirobarbiturates has been achieved via spirocyclic chiral phosphine-catalyzed asymmetric [4 + 2] annulation of barbiturate-derived alkenes with allenoates. With the use of this tool, various spirobarbiturate-cyclohexenes are obtained in good to excellent yields with excellent diastereo- and enantioselectivities. A wide range of α-substituted allenoates and barbiturate-derived alkenes were tolerated.

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.

Brønsted acid-promoted [3 + 3] cycloaddition of azomethine ylides with quinone monoimine: a practical method towards dihydrobenzoxazine derivatives

The binaphthol-derived phosphoric acid-promoted [3 + 3] cycloaddition of azomethine ylides with quinone monoimine has been achieved in the presence of 3 A MS at room temperature, providing dihydrobenzoxazine derivatives in moderate to excellent yields.

[4 + 3] Cycloaddition of Phthalazinium Dicyanomethanides with Azoalkenes Formed in Situ: Synthesis of Triazepine Derivatives

[4 + 3] cycloaddition of phthalazinium dicyanomethanides with in situ formed azoalkenes was achieved, providing an access to various 1,2,4-triazepine derivatives in moderate to excellent yields.

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).

Ag-catalyzed diastereoselective [6 + 3] cycloaddition of tropone with homoserine lactone-derived azomethine ylides: synthesis of tricyclic spiropiperidines

Ag-catalyzed [6 + 3] cycloaddition of tropone with homoserine lactone derived azomethine ylides has been developed. The reaction works efficiently under mild conditions to give tricyclic spiropiperidines in moderate to excellent yields with excellent diastereoselectivities.