Expanding the Scope of Cinchona Alkaloid-Catalyzed Enantioselective α-Aminations of Oxindoles: A Versatile Approach to Optically Active 3-Amino-2-oxindole Derivatives
作者:Tommy Bui、Mar Borregan、Carlos F. Barbas
DOI:10.1021/jo902039a
日期:2009.12.4
A cinchona alkaloid-catalyzed, highly enantioselective, α-amination of oxindoles has been developed. The reaction is general, operationally simple, and affords the desired products in high yields with good to excellent enantioselectivity. Significantly, this study provides a general catalytic method for the construction of a C−N bond at the C3 position of oxindoles as well as for the creation of a
Long-Lived Polymer-Supported Dimeric Cinchona Alkaloid Organocatalyst in the Asymmetric α-Amination of 2-Oxindoles
作者:Ravindra P. Jumde、Alessandro Mandoli
DOI:10.1021/acscatal.6b01141
日期:2016.7.1
quantitative yields and high enantiomeric purity (89–95% ee) were attained in the course of 100 reaction cycles of a polystyrene resin-supported Cinchonaalkaloidorganocatalyst in the enantioselective α-amination of 2-oxindoles with diethyl azodicarboxylate. The catalytic material proved stable for >5300 h operation time over 8 months.
New Polymer-Supported Mono- and Bis-<i>Cinchona</i>Alkaloid Derivatives: Synthesis and Use in Asymmetric Organocatalyzed Reactions
作者:Ravindra P. Jumde、Anila Di Pietro、Antonella Manariti、Alessandro Mandoli
DOI:10.1002/asia.201402924
日期:2015.2
Chinchona alkaloids and their application in the asymmetric dimerization of ketenes is reported. Six different immobilized derivatives, consisting of three dimeric and two monomeric 9‐O ethers, were prepared by “click” anchoring of soluble alkaloid precursors on to azidomethyl resins. The resulting insoluble polymer‐bound (IPB) organocatalysts were employed for promoting the dimerization of in‐situ