TY - JOUR
T1 - Stoichiometric and catalytic reactivity of Ni(6-Mes)(PPh3)2
AU - Sabater, Sara
AU - Page, Michael
AU - Mahon, Mary F
AU - Whittlesey, Michael K
PY - 2017/5/8
Y1 - 2017/5/8
N2 - The three-coordinate Ni(0) N-heterocyclic carbene complex Ni(6-Mes)(PPh3)2 (1; 6-Mes = 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) is formed in the reaction of Ni(cod)2 with a 1:2 mixture of 6-Mes and PPh3 or upon reduction of Ni(6-Mes)(PPh3)Br (2) with KOtBu. Facile substitution of PPh3 in 1 gave a range of Ni(6-Mes)(PPh3)(L) products (L = PhC≡CMe (3), PhCH═CH2 (4), Ph2CO (5), PhCHO (6)). Oxidative addition of C6F6 gave Ni(6-Mes)(PPh3)(C6F5)F (7), while 1 was also oxidized by 4-BrC6H4F to afford a mixture of 2 and Ni(6-Mes)(PPh3)(C6H4F)Br (8). Surprisingly, 1 was also oxidized upon reaction with the small 5-membered ring NHC IMe4 to give the terminal Ni(II) phosphido complex Ni(IMe4)2(PPh2)Ph (9). Compounds 1 and 5 proved to be active as a precursors for the catalytic transfer hydrogenation of ketones.
AB - The three-coordinate Ni(0) N-heterocyclic carbene complex Ni(6-Mes)(PPh3)2 (1; 6-Mes = 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) is formed in the reaction of Ni(cod)2 with a 1:2 mixture of 6-Mes and PPh3 or upon reduction of Ni(6-Mes)(PPh3)Br (2) with KOtBu. Facile substitution of PPh3 in 1 gave a range of Ni(6-Mes)(PPh3)(L) products (L = PhC≡CMe (3), PhCH═CH2 (4), Ph2CO (5), PhCHO (6)). Oxidative addition of C6F6 gave Ni(6-Mes)(PPh3)(C6F5)F (7), while 1 was also oxidized by 4-BrC6H4F to afford a mixture of 2 and Ni(6-Mes)(PPh3)(C6H4F)Br (8). Surprisingly, 1 was also oxidized upon reaction with the small 5-membered ring NHC IMe4 to give the terminal Ni(II) phosphido complex Ni(IMe4)2(PPh2)Ph (9). Compounds 1 and 5 proved to be active as a precursors for the catalytic transfer hydrogenation of ketones.
UR - https://doi.org/10.1021/acs.organomet.7b00129
U2 - 10.1021/acs.organomet.7b00129
DO - 10.1021/acs.organomet.7b00129
M3 - Article
VL - 36
SP - 1776
EP - 1783
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 9
ER -