Heteroleptic Copper-Based Complexes for Energy-Transfer Processes: <i>E</i> → <i>Z</i> Isomerization and Tandem Photocatalytic Sequences
作者:Corentin Cruché、William Neiderer、Shawn K. Collins
DOI:10.1021/acscatal.1c01983
日期:2021.7.16
Energy-transfer processes involving copper complexes are rare. Using an optimized heteroleptic copper complex, Cu(bphen)(XantPhos)BF4, photosensitized E → Z isomerization of olefins is demonstrated. The XantPhos ligand afforded sensitizers with improved catalyst stability, while the bphen ligand lengthened the excited-state lifetime. A series of 25 di- and trisubstituted alkenes underwent photoisomerization
the gram scale at a low catalyst loading. In this reaction, the copper powder not only acts as a sulfone radical initiator but also produces the catalytically active CuCl species. Mechanistic investigations and DFT calculation studies revealed that the stereoselectivity is controlled by the thermodynamic stabilities of the in situ-generated cyclic alkenyl CuII complex intermediate, which can serve as