powerful methods for allylic oxidation of alkenes. However, the inherent radical mechanism and use of peroxides as both oxidants and oxygen nucleophiles render dearth of universal catalytic systems for highly enantioselective variants and limited scope. Herein, an alternative to the asymmetric Kharasch–Sosnovsky reaction that utilized a chiral coppercatalyst and purple-LED irradiation to enable the
Kharasch-Sosnovsky 反应是烯烃烯丙基氧化最有效的方法之一。然而,固有的自由基机制和过氧化物作为氧化剂和氧亲核试剂的使用导致缺乏用于高度对映选择性变体和有限范围的通用催化系统。在此,报道了不对称 Kharasch-Sosnovsky 反应的替代方案,该反应利用手性铜催化剂和紫色 LED 照射实现 1,3-二烯、肟酯和羧酸的三组分偶联。该协议具有温和的条件、显着的范围和官能团耐受性,> 80 个例子和在药物和天然产物的后期修饰中的效用证明了这一点。详细的机理研究为基于自由基的反应途径提供了证据。
Enantioselective Radical Carbocyanation of 1,3-Dienes via Photocatalytic Generation of Allylcopper Complexes
1,3-Dienes are readily available feedstocks that are widely used in the laboratory and industry. However, the potential of converting 1,3-dienes into value-added products, especially chiral products, has not yet been fully exploited. By synergetic photoredox/copper catalysis, we achieve the first visible-light-induced, enantioselective carbocyanation of 1,3-dienes by using carboxylic acid derivatives
Enantioselective Cross-[4 + 2]-Cycloaddition/Decarboxylation of 2-Pyrones by Cooperative Catalysis of the Pd(0)/NHC Complex and Chiral Phosphoric Acid
作者:Meng-Meng Xu、Pei-Pei Xie、Jun-Xiong He、Yu-Zhen Zhang、Chao Zheng、Quan Cai
DOI:10.1021/jacs.3c14409
日期:2024.3.13
newly developed chiralphosphoricacid as the cocatalyst. Experimental investigations and computational studies support the idea that the Pd(0)/NHC complex acts as a π-Lewis base to increase the nucleophilicity of 1,3-dienes via η2 coordination, while the chiralphosphoricacid simultaneously increases the electrophilicity of 2-pyrones by hydrogen bonding. By this synergistic catalysis, the sequential