An efficient method for visible-light-initiated, nickel-catalyzed Sonogashira C(sp)-C(sp) coupling has been developed via an energy-transfer mode. Thioxanthen-9-one as a photosensitizer could significantly accelerate the arylation of alkynes with a wide range of (hetero)aryl halides in high yields. The cross-coupling reaction undergoes the stepwise oxidative addition of an arylhalide to nickel(0), transmetalation of the resulting aryl-Ni(II) halide species with Zn(II) acetylide into aryl-Ni(II) acetylide species, energy transfer from the excited state of thioxanthen-9-one to aryl-Ni(II) acetylide, and reductive elimination to the aryl alkyne.
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http://dx.doi.org/10.1021/acs.joc.0c01177 | DOI Listing |
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