区域选择性
化学
催化作用
有机化学
药物化学
废止
硫脲
部分
组合化学
作者
Shuiyuan Cheng,Zheng Ling,Tanveer Ahmad,Fang Xie,Wanbin Zhang
标识
DOI:10.1002/chem.202200128
摘要
Regioselective [3+3] annulation of alkynyl ketimines with α-cyano ketones for the synthesis of polysubstituted 4H-pyran derivatives with a quaternary CF3 -containing center has been realized by using Cu(OAc)2 as the catalyst. The novel strategy tolerates a wide range of α-CF3 alkynyl ketimines and α-cyano ketones with both aryl and alkyl substitutents. A preliminary asymmetric synthesis of chiral product 3 has been attempted by using copper and chiral thiourea as the cocatalyst with excellent yields (86-99 %) and good enantioselectivities (71-78 % ee). Furthermore, product 3 aa could be obtained on a gram-scale reaction with 75 % yield and 99 % ee after recrystallization. Several products were also transformed readily. Control experiments indicate that the reaction involves a process with a base-catalyzed or chiral thiourea-catalyzed Mannich-type reaction followed by a highly regioselective copper-catalyzed ring-closing reaction on the alkynyl moiety in a 6-endo-dig fashion.
科研通智能强力驱动
Strongly Powered by AbleSci AI