title: A Chiral N,N'-Dioxide-Zn(II) Complex Catalyzes the Enantioselective [2+2] Cycloaddition of Alkynones with Cyclic Enol Silyl Ethers.
abstract: A highly efficient enantioselective [2+2] cycloaddition between alkynones and cyclic enol silyl ethers was developed by using a chiral N,N'-dioxide-zinc(II) complex as a catalyst. This method functions well for a variety of terminal alkynes as well as cyclic enol silyl ethers, with good to excellent enantioselectivity (up to 97 % ee). This is also the first successful example for the catalytic enantioselective [2+2] cycloaddition of internal alkynes with cyclic enol silyl ethers to give fully substituted cyclobutenes. Meanwhile, the desired cyclobutene product can easily be transformed into fused cyclobutane derivatives.
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Kang
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Ge
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Lin
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China. liuxh@scu.edu.cn.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China. xmfeng@scu.edu.cn.|Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China. xmfeng@scu.edu.cn.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Feng
keywords: N,N′-dioxides; [2+2] cycloaddition; asymmetric catalysis; cycloaddition; synthetic methods