Photo-induced copper-catalyzed alkynylation and amination of remote unactivated C(sp3)-H bonds

These results suggest that a complex of nucleophile, copper, and base accounts for the photoactive species under BLED irradiation

Zhusong Cao; Jianye Li; Youwen Sun; Hanwen Zhang; Xueling Mo; Xin Cao; Guozhu Zhang

2021

Scholarcy highlights

  • Direct functionalization of inert C(sp3)-H bonds provides an atom- and step-economic strategy for the rapid construction of valuable chemical frameworks. Along with transition-metalmediated processes, radical-mediated hydrogen atom transfer has emerged as an appealing and efficient strategy to activate and functionalize C(sp3)-H in a selective manner, and signi cant progress has been made in this eld.3An installed and removable hydroxyl protecting group, thesilyl group, has been established as an excellent carbon radical precursor and widely applied in radical-type reactions. Gevorgyan pioneered remote aliphatic C–H functionalization through radical transposition processes initiated with silicontethered carbon radicals. inspiring is the photoinduced palladium-catalyzed remote C–H Heck reaction, allowing ready access to alkenyl alcohols).5a
  • Inspiring is the photoinduced palladium-catalyzed remote C–H Heck reaction, allowing ready access to alkenyl alcohols).5a. Bene tting from their electronic properties and various methods for further transformations, alkynes have been widely used as pivotal intermediates for the synthesis of complex biologically active or functional molecules
  • Remote C–H alkynylation at unactivated C–H bonds proceeding via intramolecular HAT has been explored only very recently, dominated by 1,5 transposition
  • Our group recently discovered a photo-catalytic system of copper(I) and realized the three-component carbon aKey Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Center for Excellence in Molecular Synthesis, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P
  • L1-Cu-alkyne shows absorption in the range 380–500 nm.13a In addition, the Stern–Volmer experiment indicated that the excited state of the L1-Cu-Nu complex formed in situ could be quenched by Si-iodide. These results suggest that a complex of nucleophile, copper, and base accounts for the photoactive species under BLED irradiation
  • This intermediate delivers an electron to a 1a, 2b, CuI, L1, and K2CO3 in MeCN, under N2, rt, blue LEDs, 32 h

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