Enantioselective 1,3-Dipolar Cycloaddition of Methylene­indolinones with α‑Diazomethyl­phosphonate to Access Chiral Spiro-phosphonyl­pyrazoline-oxindoles Catalyzed by Tertiary Amine Thiourea and 1,5-Diaza­bicyclo­[4.3.0]­non-5-ene

A methodology to access chiral 3,3′-spiro-phosphonyl­pyrazoline oxindoles via an asymmetric 1,3-dipolar cycloaddition reaction of substituted methylene­indolinones with α-diazomethyl­phosphonate in the catalysis of tertiary amine thiourea and 1,5-diaza­bicyclo­[4.3.0]­non-5-ene (DBN) has been established. This method exhibits high functional group compatibility, where a wide range of methylene­indolinones with various substituents and heterocyclic rings are accommodated by this reaction. The resulting chiral 3,3′-spiro-phosphonyl­pyrazoline oxindoles can be further transformed into spiro-phosphonyl­cyclo­propane oxindoles by ring contraction

Switchable Synthesis of 3‑Substituted 1<i>H</i>‑Indazoles and 3,3-Disubstituted 3<i>H</i>‑Indazole-3-phosphonates Tuned by Phosphoryl Groups

3-Alkyl/aryl-1<i>H</i>-indazoles and 3-alkyl/aryl-3<i>H</i>-indazole-3-phosphonates were synthesized efficiently through a 1,3-dipolar cycloaddition reaction between α-substituted α-diazomethylphosphonates and arynes under simple reaction conditions. The product distribution was controlled by the phosphoryl group, which acted both as a tuning group and a traceless group in the reaction

Enantioselective 1,3-Dipolar Cycloaddition of Methylene­indolinones with α‑Diazomethyl­phosphonate to Access Chiral Spiro-phosphonyl­pyrazoline-oxindoles Catalyzed by Tertiary Amine Thiourea and 1,5-Diaza­bicyclo­[4.3.0]­non-5-ene

A methodology to access chiral 3,3′-spiro-phosphonyl­pyrazoline oxindoles via an asymmetric 1,3-dipolar cycloaddition reaction of substituted methylene­indolinones with α-diazomethyl­phosphonate in the catalysis of tertiary amine thiourea and 1,5-diaza­bicyclo­[4.3.0]­non-5-ene (DBN) has been established. This method exhibits high functional group compatibility, where a wide range of methylene­indolinones with various substituents and heterocyclic rings are accommodated by this reaction. The resulting chiral 3,3′-spiro-phosphonyl­pyrazoline oxindoles can be further transformed into spiro-phosphonyl­cyclo­propane oxindoles by ring contraction

Asymmetric Reaction of α‑Diazomethylphosphonates with α‑Ketoesters To Access Optically Active α‑Diazo-β-hydroxyphosphonate Derivatives

The first example for asymmetric reaction of diazomethylphosphonates with α-ketoesters was realized in the catalysis of hydroquinidine-derived bifunctional thiourea. A methodology was established to access a series of chiral α-diazo-β-hydroxyphosphonate derivatives containing various functional groups with high enantioselectivities and yields. The resulting products could be further transformed into chiral tertiary β-hydroxyphosphonate and α-halogenated fosfomycin derivatives, especially α-fluoride analogues

Synthesis of Chiral 1,1,1-Trifluoro-<i>α,α</i>-disubstituted 2,4-Diketones via Palladium-Catalyzed Asymmetric Allylation

Trifluoromethyl ketones are important enzyme inhibitors and versatile synthons for the preparation of trifluoromethylated heterocycles and complex molecules. An efficient methodology for the synthesis of chiral 1,1,1-trifluoro-α,α-disubstituted 2,4-diketones via palladium-catalyzed allylation with allyl methyl carbonates under mild conditions has been developed. This method surmounts the major obstacle of detrifluoroacetylation, and a chiral trifluoromethyl ketone library could be rapidly built up from simple substrates in good yields and enantioselectivities, thereby offering a new choice for scientists in pharmaceutical and material industries

Synthesis of Chiral 1,1,1-Trifluoro-<i>α,α</i>-disubstituted 2,4-Diketones via Palladium-Catalyzed Asymmetric Allylation

Trifluoromethyl ketones are important enzyme inhibitors and versatile synthons for the preparation of trifluoromethylated heterocycles and complex molecules. An efficient methodology for the synthesis of chiral 1,1,1-trifluoro-α,α-disubstituted 2,4-diketones via palladium-catalyzed allylation with allyl methyl carbonates under mild conditions has been developed. This method surmounts the major obstacle of detrifluoroacetylation, and a chiral trifluoromethyl ketone library could be rapidly built up from simple substrates in good yields and enantioselectivities, thereby offering a new choice for scientists in pharmaceutical and material industries

Highly Efficient Asymmetric Mannich Reaction of Dialkyl α-Diazomethylphosphonates with <i>N</i>-Carbamoyl Imines Catalyzed by Chiral Brønsted Acids

An efficient method involving the first use of chiral phosphoric acids as catalysts in the asymmetric Mannich reaction of dialkyl diazomethylphosphonates and <i>N</i>-carbamoyl imines is developed. With only 0.1 mol % catalyst <b>1f</b>, the reaction proceeded smoothly and produced the corresponding β-amino-α-diazophosphonate with up to 97% yield and >99% <i>ee</i>

A Cation-Directed Enantioselective Sulfur-Mediated Michael/Mannich Three-Component Domino Reaction involving Chalcones as Michael Acceptors

A new approach has been developed for an asymmetric sulfur-mediated three-component intermolecular Michael/Mannich domino reaction using chalcones as Michael acceptors. This reaction is catalyzed by chiral quaternary ammonium salts derived from modified quinine and provides facile access to complex sulfur-containing compounds with three contiguous stereogenic centers in yields of up to 93%, with 95:5 <i>dr</i> and 95% <i>ee</i>. These compounds were further elaborated to give the equivalent of a chiral aza-Morita–Baylis–Hillman reaction involving chalcones and azetidines bearing four chiral centers

Asymmetric Synthesis of Polysubstituted 4-Amino- and 3,4-Diaminochromanes with a Chiral Multifunctional Organocatalyst

A series of multifunctional catalysts with two chiral diaminocyclohexane units were developed and successfully applied in the asymmetric oxa-Michael–aza-Henry cascade reaction of salicylaldimines with nitroolefins. This approach provides a simple and efficient entry to polysubstituted chiral 4-aminobenzopyrans with three consecutive stereocenters and in high yield (up to 97%) with excellent stereoselectivity (up to 98% ee and >99:1 dr). Facile access to the nonsymmetric optically pure 3,4-diaminochromanes was also obtained

Asymmetric Synthesis of Polysubstituted 4-Amino- and 3,4-Diaminochromanes with a Chiral Multifunctional Organocatalyst

A series of multifunctional catalysts with two chiral diaminocyclohexane units were developed and successfully applied in the asymmetric oxa-Michael–aza-Henry cascade reaction of salicylaldimines with nitroolefins. This approach provides a simple and efficient entry to polysubstituted chiral 4-aminobenzopyrans with three consecutive stereocenters and in high yield (up to 97%) with excellent stereoselectivity (up to 98% ee and >99:1 dr). Facile access to the nonsymmetric optically pure 3,4-diaminochromanes was also obtained