Chiral phosphoric acid catalyzed enantioselective addition of thiols to in situ generated ketimines: Synthesis of N , S -ketals
作者:Rajshekhar A. Unhale、Nagaraju Molleti、Nirmal K. Rana、Sivasankaran Dhanasekaran、Subhrajyoti Bhandary、Vinod K. Singh
DOI:10.1016/j.tetlet.2016.11.114
日期:2017.1
The chiral Brønsted acid catalyzed enantioselective 1,2-addition of thiols to in situgenerated ketimines, derived from 3-hydroxyisoindolinones, has been studied. The protocol provides a variety of isoindolinone-derived N,S-ketals in up to 98% yield and up to 99% enantioselectivity. The products have been converted to a known non-nucleoside HIV-1 reverse transcriptase inhibitor and a 1,3-thiazine derivative
A chiral Brønsted acid-catalyzed highly enantioselective Mannich-type reaction of α-diazo esters with <i>in situ</i> generated <i>N</i>-acyl ketimines
作者:Rajshekhar A. Unhale、Milon M. Sadhu、Sumit K. Ray、Rayhan G. Biswas、Vinod K. Singh
DOI:10.1039/c8cc01436a
日期:——
A chiral phosphoric acid-catalyzed asymmetricMannich-typereaction of α-diazo esters with in situ generated N-acyl ketimines, derived from 3-hydroxyisoindolinones has been demonstrated in this communication. A variety of isoindolinone-based α-amino diazo esters bearing a quaternary stereogenic center were afforded in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee). Furthermore
A chiral SPINOL derived phosphoric acid-catalyzed asymmetric N-alkylation reaction of indoles with cyclic α-diaryl-substituted N-acyl imines, which are generated in situ from 3-aryl 3-hydroxyisoindolinones, has been demonstrated. The transformation proceeds smoothly with a broad range of indoles and isoindolinone alcohols. A variety of indole derived N-alkylated tetrasubstituted chiral aminals were
Enantioselective Hydrophosphonylation of <i>in Situ</i> Generated <i>N</i>-Acyl Ketimines Catalyzed by BINOL-Derived Phosphoric Acid
作者:Arun Suneja、Rajshekhar A. Unhale、Vinod K. Singh
DOI:10.1021/acs.orglett.6b03623
日期:2017.2.3
An efficient route to pharmacologically interesting isoindolinone-based α-amino phosphonates is described via asymmetric hydrophosphonylation of in situ generated ketimines catalyzed by BINOL-derivedphosphoricacid. The reaction proceeds smoothly at ambient temperature affording a variety of α-amino phosphonates with a quaternary stereogenic center embedded in isoindolinone motif in high yields with
Synthesis of Spiroisoindolinones via Ru(II)-Catalyzed Spiroannulation of <i>N</i>-Acyl Ketimines with Aryl Isocyanates/Isothiocyanates through Aromatic C–H Bond Activation
作者:Zahid Ahmad Khan、Vinod K. Singh
DOI:10.1021/acs.joc.3c02275
日期:2023.12.15
Herein, we disclose the first report on Ru(II)-catalyzed amidation/thioamidation of 3-hydroxy-3-arylisoindolinones with isocyanates/isothiocyanates, respectively. The reaction furnishes spiroisoindolinones via sequential C–H functionalization of ortho C–H bond followed by intramolecular cyclization in moderate to high yields (up to 94%). Moreover, the developed strategy is highly atom-economical and