Synthesis of Diaryl Diazaphosphonates via 1,6-Hydrophosphonylation of <i>p</i>‑Quinone Methides with <i>N</i>‑Heterocyclic Phosphine–Thioureas

A mild, efficient method for the synthesis of diaryl diazaphosphonates via 1,6-hydrophosphonylation/aromatization of <i>p</i>-quinone methides (<i>p</i>-QMs) with <i>N</i>-heterocyclic phosphine–thioureas has been developed. This transformation proceeds without any additive or catalyst under mild reaction conditions and tolerates a wide range of <i>p</i>-QMs. This methodology provides a straightforward access to diaryl phosphonate derivatives in good to excellent yields (up to 99%)

Enantioselective organocatalytic Aldol reaction of unactivated ketones with isatins

Enantioselective organocatalytic direct aldol reaction of unactivated ketones with various isatin derivatives was developed using cinchonine based urea ligand employing a noncovalent catalysis mechanism. Using this protocol we can access functionalized 3-alkyl-3-hydroxyindolin-2-ones in high yields with good to excellent enantioselectivities

Highly Enantioselective Conjugate Addition of Malononitrile to 2‑Enoylpyridines with Bifunctional Organocatalyst

An efficient enantioselective conjugate addition of malononitrile to a range of β-substituted 2-enoylpyridines catalyzed by cinchona alkaloid-based bifunctional urea catalysts has been developed. Both enantiomers of the products could be achieved with the same level of enantioselectivity by using pseudoenantiomeric catalysts in up to 97% ee and in excellent yields. One of the enantioenriched products has been transformed to a highly functionalized piperidone derivative

Enantioselective Synthesis of Highly Substituted Chromans via the Oxa-Michael–Michael Cascade Reaction with a Bifunctional Organocatalyst

A highly enantioselective synthesis of chiral chroman derivatives via an oxa-Michael–Michael cascade reaction has been developed using a bifunctional thiourea organocatalyst. The products were obtained with excellent enantioselectivities (up to >99%), good yields (up to 95%), and diastereoselectivities (up to 5:1)

Enantioselective Synthesis of Coumarin Derivatives by PYBOX-DIPH-Zn(II) Complex Catalyzed Michael Reaction

A potential pharmacologically active chiral 3-substituted 4-hydroxy-2-oxo-2<i>H</i>-chromene skeleton has been synthesized by enantioselective Michael addition catalyzed by PYBOX-DIPH-Zn­(OTf)₂ complex. The methodology has successfully been employed in the synthesis of (<i>R</i>)-Warfarin and another related compounds

Enantioselective Synthesis of Coumarin Derivatives by PYBOX-DIPH-Zn(II) Complex Catalyzed Michael Reaction

A potential pharmacologically active chiral 3-substituted 4-hydroxy-2-oxo-2<i>H</i>-chromene skeleton has been synthesized by enantioselective Michael addition catalyzed by PYBOX-DIPH-Zn­(OTf)₂ complex. The methodology has successfully been employed in the synthesis of (<i>R</i>)-Warfarin and another related compounds

Enantioselective Synthesis of Coumarin Derivatives by PYBOX-DIPH-Zn(II) Complex Catalyzed Michael Reaction

A potential pharmacologically active chiral 3-substituted 4-hydroxy-2-oxo-2<i>H</i>-chromene skeleton has been synthesized by enantioselective Michael addition catalyzed by PYBOX-DIPH-Zn­(OTf)₂ complex. The methodology has successfully been employed in the synthesis of (<i>R</i>)-Warfarin and another related compounds