Chiral Bis(imidazolinyl)phenyl NCN Pincer Rhodium(III) Catalysts for Enantioselective Allylation of Aldehydes and Carbonyl–Ene Reaction of Trifluoropyruvates
作者:Tao Wang、Xin-Qi Hao、Juan-Juan Huang、Jun-Long Niu、Jun-Fang Gong、Mao-Ping Song
DOI:10.1021/jo4014194
日期:2013.9.6
Chiral NCN pincer rhodium(III) complexes with bis(imidazolinyl)phenyl ligands were found to be effective catalysts for the allylation of a variety of electronically and structurally diverse aldehydes with allyltributyltin, giving the corresponding optically active homoallylic alcohols in high yields with enantioselectivities of up to 97% ee. These complexes were also applied in the carbonyl–ene reaction
Asymmetric Latent Carbocation Catalysis with Chiral Trityl Phosphate
作者:Jian Lv、Qichao Zhang、Xingren Zhong、Sanzhong Luo
DOI:10.1021/jacs.5b11085
日期:2015.12.16
Stable carbocations such as tritylium ions have been widely explored as organic Lewisacid catalysts and reagents in organic synthesis. However, achieving asymmetric carbocation catalysis remains elusive ever since they were first identified over one century ago. The challenges mainly come from their limited compatibility, scarcity of chiral carbocations, as well as the extremely low barrier to racemization
Asymmetric Calcium Catalysis: Highly Enantioselective Carbonyl-Ene and Friedel-Crafts Reactions for the Synthesis of Quaternary α-Hydroxy Esters Bearing a Trifluoromethyl Group
Enantioselectivecalcium‐catalyzed addition reactions of styrene and indole derivatives with trifluoropyruvates have been developed. The alkaline‐earth metal‐catalyzed reactions proceed smoothly to afford the corresponding products in high yields and with good to excellent enantioselectivities under mild reaction conditions.