An air-stable binary Ni(0)–olefin catalyst

Ni(COD)(DQ): An Air‐Stable 18‐Electron Nickel(0)–Olefin Precatalyst

“…Indeed, when we evaluated Ni(COD)(DQ) as a replacement for NiCl 2 (dppp) in the catalytic coupling of HBpin and an aryl chloride, we observed comparable yields to an original report by Murata . Analogously, Ni(COD)(DQ) performed similarly to both Ni(COD) 2 and Ni( F stb) 3 in a substrate‐directed C(aryl)−H activation/alkyne annulation developed by Chatani and colleagues, in which PPh 3 and the bidentate pyridyl amide directing group presumably serve as ligands around nickel . To evaluate the performance of Ni(COD)(DQ) in alkene functionalization reactions, we implemented it in the 8‐aminoquinoline‐directed hydroarylation of an unactivated alkene as reported originally by Zhao and co‐workers and found the yield to be comparable to that reported using Ni(COD) 2 as catalyst .…”

“…These practical features of Ni(COD)(DQ) when viewed through the lens of the versatile reactivity described herein make it a valuable addition to the growing repertoire of nickel precatalysts. In parallel to this study, Cornella and colleagues described a 16‐electron nickel(0)–olefin complex, Ni( F stb) 3 ( F stb= trans ‐1,2‐bis(4‐(trifluoromethyl)phenyl)ethane) and documented its ability to serve as a precatalyst for several different types of reactions …”

“…The origin of attenuated reactivity in these cases is currently under investigation. In one case ( 1 h ), it was also possible to make a direct comparison to Ni( F stb) 3 , and for this product Ni(COD)(DQ) offered similarly high yield. Again, we note that further optimization was not conducted, which may be necessary for different precatalyst complexes to optimize yield.…”

“…Yields with [(dppf)Ni(cinnamyl)Cl] and Ni( F stb) 3 are taken from refs. . [c] Method A: K 3 PO 4 (1.5 equiv), dioxane (0.4 m ), 80 °C, 8 h; Method B: K 2 CO 3 (1.5 equiv), MeCN (0.4 m ), 50 °C, 12 h; the method is specified in parentheses after the compound number.…”

“…, under the same conditions in comparable yield to Ni(COD) 2 . With 4‐chlorobenzotrifluoride ( 2 e ), an electrophile not included in the original Buchwald paper, it has been reported that the use of SIPr delivers high yields with morpholine as coupling partner . Indeed, with in situ ligation of SIPr, Ni(COD) 2 and Ni(COD)(DQ) both facilitated C−N coupling in comparable yields ( 2 d – f ).…”