Chemical Science p. 1260 - 1268 (2020)
Update date:2022-08-31
Topics:
Dong, Yuyang
Lukens, James T.
Clarke, Ryan M.
Zheng, Shao-Liang
Lancaster, Kyle M.
Betley, Theodore A.
Metalation of the deprotonated dipyrrin (AdFL)Li with NiCl2(py)2 afforded the divalent Ni product (AdFL)NiCl(py)2 (1) (AdFL: 1,9-di(1-adamantyl)-5-perfluorophenyldipyrrin; py: pyridine). To generate a reactive synthon on which to explore oxidative group transfer, we used potassium graphite to reduce 1, affording the monovalent Ni synthon (AdFL)Ni(py) (2) and concomitant production of a stoichiometric equivalent of KCl and pyridine. Slow addition of mesityl- or 1-adamantylazide in benzene to 2 afforded the oxidized Ni complexes (AdFL)Ni(NMes) (3) and (AdFL)Ni(NAd) (4), respectively. Both 3 and 4 were characterized by multinuclear NMR, EPR, magnetometry, single-crystal X-ray crystallography, theoretical calculations, and X-ray absorption spectroscopies to provide a detailed electronic structure picture of the nitrenoid adducts. X-ray absorption near edge spectroscopy (XANES) on the Ni reveals higher energy Ni 1s → 3d transitions (3: 8333.2 eV; 4: 8333.4 eV) than NiI or unambiguous NiII analogues. N K-edge X-ray absorption spectroscopy performed on 3 and 4 reveals a common low-energy absorption present only for 3 and 4 (395.4 eV) that was assigned via TDDFT as an N 1s promotion into a predominantly N-localized, singly occupied orbital, akin to metal-supported iminyl complexes reported for iron. On the continuum of imido (i.e., NR2-) to iminyl (i.e., 2NR-) formulations, the complexes are best described as NiII-bound iminyl species given the N K-edge and TDDFT results. Given the open-shell configuration (S = 1/2) of the iminyl adducts, we then examined their propensity to undergo nitrenoid-group transfer to organic substrates. The adamantyl complex 4 readily consumes 1,4-cyclohexadiene (CHD) via H-atom abstraction to afford the amide (AdFL)Ni(NHAd) (5), whereas no reaction was observed upon treatment of the mesityl variant 3 with excess amount of CHD over 3 hours. Toluene can be functionalized by 4 at room temperature, exclusively affording the N-1-adamantyl-benzylidene (6). Slow addition of the organoazide substrate (4-azidobutyl)benzene (7) with 2 exclusively forms 4-phenylbutanenitrile (8) as opposed to an intramolecular cyclized pyrrolidine, resulting from facile β-H elimination outcompeting H-atom abstraction from the benzylic position, followed by rapid H2-elimination from the intermediate Ni hydride ketimide intermediate.
View MoreGeen Chemical Technology Co., Ltd
Contact:86-769-21660847
Address:1408, Yingfeng Commercial Center, Nancheng District
Hangzhou Pharma & Chem Co.,Ltd.
Contact:+86-571-87040515
Address:No,139Qingchun Rd
Huaihua Baohua Biotechnology Co.,Ltd
website:http://www.baochengchem.com
Contact:86-519-82698291
Address:HouYang chemical development zone,Jintan,Jiangsu,China (213200)
Taizhou Shengxing Chempharm Co.,Ltd
Contact:+86-576-88516600
Address:Yantou Chemical Zone Jiaojiang Taizhou Zhejiang China
Contact:+86-25-8776 0031
Address:3-2001 Jiaye Int'l Town, 158 Lushan Road,Nanjing, 210019, China
Doi:10.1016/j.tetlet.2007.09.096
(2007)Doi:10.1080/14756366.2020.1847100
(2021)Doi:10.1021/ol403275k
(2014)Doi:10.1016/j.tet.2007.10.034
(2007)Doi:10.1021/ja972806d
(1997)Doi:10.1126/science.1241764
(2013)