Primary Amine/CSA Ion Pair: A Powerful Catalytic System for the Asymmetric Enamine Catalysis
作者:Chen Liu、Qiang Zhu、Kuo-Wei Huang、Yixin Lu
DOI:10.1021/ol200747x
日期:2011.5.20
A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (−)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities
Enantioselective α-Amination of Branched Aldehydes Promoted by Simple Chiral Primary Amino Acids
作者:Ji-Ya Fu、Qing-Chuan Yang、Qi-Lin Wang、Jun-Nan Ming、Fei-Ying Wang、Xiao-Ying Xu、Li-Xin Wang
DOI:10.1021/jo102361h
日期:2011.6.3
A series of simple chiral primary amino acids were first successfully applied to promote the enantioselectiveα-amination of branchedaldehydes with azadicarboxylates and the desired adducts bearing quaternary stereogenic centers were obtained in excellent yields (up to 99%) and enantioselectivities (up to 97% ee).
Effective construction of quaternary stereocenters by highly enantioselective α-amination of branched aldehydes
作者:Ji-Ya Fu、Xiao-Ying Xu、Yan-Chun Li、Qing-Chun Huang、Li-Xin Wang
DOI:10.1039/c0ob00406e
日期:——
A highly efficient enantioselectiveα-amination of branchedaldehydes with azadicarboxylates promoted by chiral proline-derived amide thiourea bifunctional catalysts was developed for the first time, affording the adducts bearing quaternary stereogenic centers with excellent yields (up to 99%) and enantioselectivities (up to 97% ee).
Chiral α-Arylethanamines: An Organocatalyst for the Enantioselective α-Amination of Branched Aldehydes
作者:Ji-Ya Fu、Qi-Lin Wang、Lin Peng、Yong-Yuan Gui、Fan Wang、Fang Tian、Xiao-Ying Xu、Li-Xin Wang
DOI:10.1002/ejoc.201201701
日期:2013.5
α-Arylethanamines were investigated as organocatalysts for the α-amination of branchedaldehydes with azodicarboxylates. Optimization identified (R)-1-(1-naphthyl)ethanamine (1g) as an effective and enantioselectiveorganocatalyst; multifunctional chiral quaternary amino aldehydes were successfully obtained in excellent yields (up to 99 %) and with excellent enantioselectivities (up to 98 % ee).
of α,α-disubstituted aldehydes with azodicarboxylates promoted by a chiral carbamate-monoprotected cyclohexa-1,2-diamine as organocatalyst has been developed. The process was carried out without any solvent, and the corresponding α,α-disubstituted α-nitrogenated aldehydes were obtained with excellent yields and enantioselectivities up to 99% ee. The sustainability of the procedure was established through