Journal of the American Chemical Society p. 19540 - 19550 (2020)
Update date:2022-09-26
Topics:
Le Vaillant, Franck
Reijerse, Edward J.
Leutzsch, Markus
Cornella, Josep
In this article, we investigated the I2-promoted cyclic dialkyl ether formation from 6-membered oxanickelacycles originally reported by Hillhouse. A detailed mechanistic investigation based on spectroscopic and crystallographic analysis revealed that a putative reductive elimination to forge C(sp3)-OC(sp3) using I2 might not be operative. We isolated a paramagnetic bimetallic NiIII intermediate featuring a unique Ni2(OR)2 (OR = alkoxide) diamond-like core complemented by a μ-iodo bridge between the two Ni centers, which remains stable at low temperatures, thus permitting its characterization by NMR, EPR, X-ray, and HRMS. At higher temperatures (>-10 °C), such bimetallic intermediate thermally decomposes to afford large amounts of elimination products together with iodoalkanols. Observation of the latter suggests that a C(sp3)-I bond reductive elimination occurs preferentially to any other challenging C-O bond reductive elimination. Formation of cyclized THF rings is then believed to occur through cyclization of an alcohol/alkoxide to the recently forged C(sp3)-I bond. The results of this article indicate that the use of F+ oxidants permits the challenging C(sp3)-OC(sp3) bond formation at a high-valent nickel center to proceed in good yields while minimizing deleterious elimination reactions. Preliminary investigations suggest the involvement of a high-valent bimetallic NiIII intermediate which rapidly extrudes the C-O bond product at remarkably low temperatures. The new set of conditions permitted the elusive synthesis of diethyl ether through reductive elimination, a remarkable feature currently beyond the scope of Ni.
View MoreShanghai Massive Chemical Technology Co., Ltd.
website:http://www.massivechem.com/
Contact:+86 21 34943721
Address:Room 435, 4th floor, Building 9, No. 2568 Gudai Road,Minhang District, Shanghai,
Zhejiang Kente Chemical Co.,Ltd.
Contact:86-0576-87651912
Address:No.7, Fengxi West Road, Modern Industrial Zone
Zhejiang Allied Chemical Co.,Ltd
Contact:18967038207
Address:Area A-30, High-tech Industrial Park, Quzhou, Zhejiang, China.
website:http://www.amadischem.com
Contact:86-571-89925085
Address:Watts Cosine.No.166.Xiangmao Road.
Jiangxi Hessence Chemicals Co., Ltd.
Contact:+86 796 3511924
Address:Chengxi Industrial Park, Jishui County, Jiangxi Province 331600 China.
Doi:10.1021/jo00217a005
(1985)Doi:10.1016/0008-6215(85)85221-6
(1985)Doi:10.1016/j.ejmech.2013.08.020
(2013)Doi:10.1021/cb4007562
(2014)Doi:10.1016/S0040-4020(02)01123-7
(2002)Doi:10.1016/S0223-5234(97)89856-X
(1996)