TY - JOUR
T1 - Ni(I)-X Complexes Bearing a Bulky α-Diimine Ligand
T2 - Synthesis, Structure, and Superior Catalytic Performance in the Hydrogen Isotope Exchange in Pharmaceuticals
AU - Zarate, Cayetana
AU - Yang, Haifeng
AU - Bezdek, Máté J.
AU - Hesk, David
AU - Chirik, Paul J.
N1 - Funding Information:
A United States National Science Foundation (NSF) Grant Opportunities for Academic Liaison with Industry (GOALI) grant (CHE-1564379) is acknowledged for financial support. C.Z. acknowledges support from a Foundation Ramón Areces postdoctoral fellowship. M.J.B. thanks the Natural Sciences and Engineering Research Council of Canada for a predoctoral fellowship (PGS-D). We thank Kenith Conover and István Pelczer (Princeton University) for assistance with the acquisition of NMR data.
Funding Information:
A United States National Science Foundation (NSF) Grant Opportunities for Academic Liaison with Industry (GOALI) grant (CHE-1564379) is acknowledged for financial support. C.Z. acknowledges support from a Foundation Ramoń Areces postdoctoral fellowship. M.J.B. thanks the Natural Sciences and Engineering Research Council of Canada for a predoctoral fellowship (PGS-D). We thank Kenith Conover and Istvań Pelczer (Princeton University) for assistance with the acquisition of NMR data.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/3/27
Y1 - 2019/3/27
N2 - The synthesis and spectroscopic characterization of a family of Ni-X (X = Cl, Br, I, H) complexes supported by the bulky α-diimine chelate N,N′-bis(1R,2R,3R,5S)-(-)-isopinocampheyl-2,3-butanediimine ( ipc ADI) are described. Diimine-supported, three-coordinate nickel(I)-X complexes have been proposed as key intermediates in a host of catalytic transformations such as C-C and C-heteroatom cross-coupling and C-H functionalization but have until now remained synthetically elusive. A combination of structural, spectroscopic, electrochemical, and computational studies were used to establish the electronic structure of each monomeric [( ipc ADI)NiX] (X = Cl, Br, I) complex as a nickel(I) derivative supported by a redox-neutral α-diimine chelate. The dimeric nickel hydride, [( ipc ADI)Ni(μ 2 -H)] 2 , was prepared and characterized by X-ray diffraction; however, magnetic measurements and 1 H NMR spectroscopy support monomer formation at ambient temperature in THF solution. This nickel hydride was used as a precatalyst for the hydrogen isotope exchange (HIE) of C-H bonds in arenes and pharmaceuticals. By virtue of the multisite reactivity and high efficiency, the new nickel precatalyst provided unprecedented high specific activities (50-99 Ci/mmol) in radiolabeling, meeting the threshold required for radioligand binding assays. Use of air-stable and readily synthesized nickel precursor, [( ipc ADI)NiBr 2 ], broad functional group tolerance, and compatibility with polar protic solvents are additional assets of the nickel-catalyzed HIE method.
AB - The synthesis and spectroscopic characterization of a family of Ni-X (X = Cl, Br, I, H) complexes supported by the bulky α-diimine chelate N,N′-bis(1R,2R,3R,5S)-(-)-isopinocampheyl-2,3-butanediimine ( ipc ADI) are described. Diimine-supported, three-coordinate nickel(I)-X complexes have been proposed as key intermediates in a host of catalytic transformations such as C-C and C-heteroatom cross-coupling and C-H functionalization but have until now remained synthetically elusive. A combination of structural, spectroscopic, electrochemical, and computational studies were used to establish the electronic structure of each monomeric [( ipc ADI)NiX] (X = Cl, Br, I) complex as a nickel(I) derivative supported by a redox-neutral α-diimine chelate. The dimeric nickel hydride, [( ipc ADI)Ni(μ 2 -H)] 2 , was prepared and characterized by X-ray diffraction; however, magnetic measurements and 1 H NMR spectroscopy support monomer formation at ambient temperature in THF solution. This nickel hydride was used as a precatalyst for the hydrogen isotope exchange (HIE) of C-H bonds in arenes and pharmaceuticals. By virtue of the multisite reactivity and high efficiency, the new nickel precatalyst provided unprecedented high specific activities (50-99 Ci/mmol) in radiolabeling, meeting the threshold required for radioligand binding assays. Use of air-stable and readily synthesized nickel precursor, [( ipc ADI)NiBr 2 ], broad functional group tolerance, and compatibility with polar protic solvents are additional assets of the nickel-catalyzed HIE method.
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U2 - 10.1021/jacs.9b00939
DO - 10.1021/jacs.9b00939
M3 - Article
C2 - 30827090
AN - SCOPUS:85063123588
SN - 0002-7863
VL - 141
SP - 5034
EP - 5044
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 12
ER -