Enantioselective Synthesis of Coumarin Derivatives by PYBOX-DIPH-Zn(II) Complex Catalyzed Michael Reaction
作者:Sumit K. Ray、Pradeep K. Singh、Nagaraju Molleti、Vinod K. Singh
DOI:10.1021/jo301513x
日期:2012.10.5
A potential pharmacologically active chiral 3-substituted 4-hydroxy-2-oxo-2H-chromene skeleton has been synthesized by enantioselectiveMichael addition catalyzed by PYBOX-DIPH-Zn(OTf)2 complex. The methodology has successfully been employed in the synthesis of (R)-Warfarin and another related compounds.
Enantioselective Mukaiyama–Michael with 2-enoyl pyridine N-oxides catalyzed by PYBOX-DIPH-Zn(ii)-complexes at ambient temperature
作者:Subhrajit Rout、Sumit K. Ray、Vinod K. Singh
DOI:10.1039/c3ob40445e
日期:——
A chiral PYBOX-DIPH-Zn(II) catalyzedenantioselectiveMukaiyama–Michaelreaction of acyclic silylenolethers with 2-enoylpyridine N-oxides has been studied in external additive free conditions at ambient temperature. The methodology offers straightforward access to a variety of functionalized chiral 1,5-dicarbonyl compounds, which could easily be elaborated into synthetically viable pyrones via hydrolysis
Asymmetric Direct Vinylogous Michael Addition to 2-Enoylpyridine <i>N</i>-Oxides Catalyzed by Bifunctional Thio-Urea
作者:Subhrajit Rout、Sumit K. Ray、Rajshekhar A. Unhale、Vinod K. Singh
DOI:10.1021/ol5025794
日期:2014.11.7
Catalytic enantioselectivedirectvinylogousMichaeladdition of α,α-dicyanoalkenes to 2-enoylpyridine N-oxides with a bifunctional organocatalyst is described. The methodology offers an efficient way to install an asymmetric carbon–carbon bond at the γ-position of α,α-dicyanoalkenes in excellent regio-, diastereo-, and enantioselectivity. Further, application in desymmetrization of achiral α,α-dicyanoalkene