Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 142, Issue 46, Pages 19540-19550Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jacs.0c07381
Keywords
-
Categories
Funding
- Max-Planck-Gesellschaft
- Max-Planck-Institut fur Kohlenforschung
- Fonds der Chemischen Industrie (VCI-FCI)
- Swiss National Science Foundation [184406]
Ask authors/readers for more resources
In this article, we investigated the I-2-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(sp(3))-OC(sp(3)) using I-2 might not be operative. We isolated a paramagnetic bimetallic Ni-III intermediate featuring a unique Ni-2(OR)(2) (OR = alkoxide) diamond-like core complemented by a mu-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 degrees C), such bimetallic intermediate thermally decomposes to afford large amounts of elimination products together with iodoalkanols. Observation of the latter suggests that a C(sp(3))-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(sp(3))-I bond. The results of this article indicate that the use of F+ oxidants permits the challenging C(sp(3))-OC(sp(3)) 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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available