TY - JOUR
T1 - Enzyme-like catalysis via ternary complex mechanism
T2 - Alkoxy-bridged dinuclear cobalt complex mediates chemoselective O-esterification over N-amidation
AU - Hayashi, Yukiko
AU - Santoro, Stefano
AU - Azuma, Yuki
AU - Himo, Fahmi
AU - Ohshima, Takashi
AU - Mashima, Kazushi
PY - 2013/4/24
Y1 - 2013/4/24
N2 - Hydroxy group-selective acylation in the presence of more nucleophilic amines was achieved using acetates of first-row late transition metals, such as Mn, Fe, Co, Cu, and Zn. Among them, cobalt(II) acetate was the best catalyst in terms of reactivity and selectivity. The combination of an octanuclear cobalt carboxylate cluster [Co4(OCOR)6O]2 (2a: R = CF3, 2b: R = CH3, 2c: R = tBu) with nitrogen-containing ligands, such as 2,2′-bipyridine, provided an efficient catalytic system for transesterification, in which an alkoxide-bridged dinuclear complex, Co2(OCOtBu)2(bpy) 2(μ2-OCH2-C6H4-4- CH3)2 (10), was successfully isolated as a key intermediate. Kinetic studies and density functional theory calculations revealed Michaelis-Menten behavior of the complex 10 through an ordered ternary complex mechanism similar to dinuclear metallo-enzymes, suggesting the formation of alkoxides followed by coordination of the ester.
AB - Hydroxy group-selective acylation in the presence of more nucleophilic amines was achieved using acetates of first-row late transition metals, such as Mn, Fe, Co, Cu, and Zn. Among them, cobalt(II) acetate was the best catalyst in terms of reactivity and selectivity. The combination of an octanuclear cobalt carboxylate cluster [Co4(OCOR)6O]2 (2a: R = CF3, 2b: R = CH3, 2c: R = tBu) with nitrogen-containing ligands, such as 2,2′-bipyridine, provided an efficient catalytic system for transesterification, in which an alkoxide-bridged dinuclear complex, Co2(OCOtBu)2(bpy) 2(μ2-OCH2-C6H4-4- CH3)2 (10), was successfully isolated as a key intermediate. Kinetic studies and density functional theory calculations revealed Michaelis-Menten behavior of the complex 10 through an ordered ternary complex mechanism similar to dinuclear metallo-enzymes, suggesting the formation of alkoxides followed by coordination of the ester.
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U2 - 10.1021/ja400367h
DO - 10.1021/ja400367h
M3 - Article
C2 - 23581978
AN - SCOPUS:84876698288
SN - 0002-7863
VL - 135
SP - 6192
EP - 6199
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 16
ER -