Qin Yin

Enantioselective Synthesis of Planar Chiral Ferrocenes via Pd(0)-Catalyzed Intramolecular Direct C–H Bond Arylation

A highly efficient synthesis of planar chiral ferrocenes by enantioselective Pd(0)-catalyzed direct C-H arylation from readily available starting materials under mild reaction conditions was developed (up to 99% yield, 99% ee). The products can be easily transformed to the highly efficient planar ferrocene ligands, which have demonstrated high efficiency in Pd-catalyzed asymmetric allylic alkylation and amination reactions.

Chiral phosphoric acid-catalysed Friedel–Crafts alkylation reaction of indoles with racemic spiro indolin-3-ones

Chiral phosphoric acid-catalysed Friedel–Crafts alkylation reactions of indoles, pyrrole and 3-(dimethylamino)phenol with racemic spiro indolin-3-ones have been realised. With 5 mol% (S)-TRIP, Friedel–Crafts adducts bearing a quaternary stereocentre were obtained in up to 99% yield and 99% ee. The reaction features readily available, stable starting materials and delivers synthetically useful but challenging products.

Asymmetric Dearomatization of β-Naphthols through an Amination Reaction Catalyzed by a Chiral Phosphoric Acid†

A highly efficient catalytic asymmetric dearomatization of naphthols by means of an electrophilic amination reaction catalyzed by chiral phosphoric acid is presented. This protocol provides a facile access to functionalized β-naphthalenone compounds with a chiral quaternary carbon center in excellent yields and enantioselectivity (up to 99% yield, up to 96% ee).

Enantioselective Chlorocyclization of Indole Derived Benzamides for the Synthesis of Spiro-indolines

(DHQD)2PHAL catalyzed enantioselective chlorocyclization of indole derived benzamides was realized. Spiro-indolines containing a continuous quaternary carbon center and tertiary carbon center were obtained in good yields with excellent enantioselectivity (up to 90% yield and 96% ee).

Asymmetric chlorocyclization of indole-3-yl-benzamides for the construction of fused indolines.

(DHQD)2PHAL catalyzed enantioselective chlorocyclization of indole-3-yl-benzamides was realized. Fused indolines containing a continuous quaternary carbon center and tertiary carbon center were obtained in good yields with excellent enantioselectivity (up to 98% yield and >99% ee).

Asymmetric synthesis of tetrahydro-β-carbolines via chiral phosphoric acid catalyzed transfer hydrogenation reaction.

Chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of hydroxylactams has been realized to provide enantioenriched tetrahydro-β-carbolines in dioxane at room temperature (up to 94% yield, 90% ee).

Friedel-Crafts-Type Intermolecular C-H Silylation of Electron-Rich Arenes Initiated by Base-Metal Salts.

An electrophilic aromatic substitution (SE Ar) with a catalytically generated silicon electrophile is reported. Essentially any commercially available base-metal salt acts as an initiator/catalyst when activated with NaBAr(F)4. The thus-generated Lewis acid then promotes the SE Ar of electron-rich arenes with hydrosilanes but not halosilanes. This new C-H silylation was optimized for FeCl2/NaBAr(F)4, affording good yields at catalyst loadings as low as 0.5 mol %. The procedure is exceedingly straightforward and comes close to typical Friedel-Crafts methods, where no added base is needed to absorb the released protons.

Asymmetric Chlorination/Ring Expansion for the Synthesis of α-Quaternary Cycloalkanones

A highly enantioselective chlorination/ring expansion cascade for the construction of cycloalkanones with an all-carbon quaternary center was realized (up to 97% ee). Oxa-cyclobutanol substrates were employed for the first time in the ring expansion reactions, affording the functionalized dihydrofuranones in excellent enantioselectivity.

Intramolecular alkene electrophilic bromination initiated ipso-bromocyclization for the synthesis of functionalized azaspirocyclohexadienones.

Intramolecular alkene electrophilic bromination initiated dearomative cyclization has been realized in the presence of DBDMH to provide functionalized azaspirocyclohexadienones in excellent yields under mild conditions.

N-alkylation of indole via ring-closing metathesis/isomerization/Mannich cascade under ruthenium/chiral phosphoric acid sequential catalysis

A sequential catalysis by combining the Zhan-1B catalyst with chiral phosphoric acid has been utilized for N-alkylation of indole through a ring-closing metathesis/double bond isomerization/Mannich reaction cascade. Enantioenriched γ-lactams were synthesized in up to 92% yield and 95% ee.