formal Betti reaction between variously substituted phenols and benzophenone-derived imines to afford α-triphenylmethylamines is reported. The key to the success of this transformation is the in situ generation of the reactive benzophenone iminium species under organocatalytic conditions. Different phenols reacted smoothly, enabling the synthesis of an array of α-triphenylmethylamines, which are highly
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
BF<sub>3</sub>·OEt<sub>2</sub>-Catalyzed Vinyl Azide Addition to in Situ Generated <i>N</i>-Acyl Iminium Salts: Synthesis of 3-Oxoisoindoline-1-acetamides
作者:Deb Kumar Das、Vinod Kumar Kannaujiya、Milon M. Sadhu、Sumit Kumar Ray、Vinod K. Singh
DOI:10.1021/acs.joc.9b02127
日期:2019.12.20
BF3·OEt2-catalyzed nucleophilic addition of vinyl azides to in situ generated N-acyl iminium salts obtained from 3-hydroxyisoindolinones is described in this article. The procedure is operationally simple, mild, additive, and metal-free. The reaction proceeds smoothly at ambient temperature with a wide range of 3-hydroxyisoindol-1-ones and vinyl azides to afford 3-oxoisoindoline-1-acetamides (32 examples)
Asymmetricaddition of indoles to cyclic α-diaryl-substituted N-acyl imines, which are generated in situ from 3-aryl 3-hydroxyisoindolinones, is described. The transformation proceeds smoothly with a broad range of indoles and isoindolinone alcohols using a SPINOL-derived chiral Brønsted acid catalyst to afford α-tetrasubstituted (3-indolyl)(diaryl)methanamines in excellent yields and enantioselectivities