How and Why Does Ni0 Promote Smooth Etheric CO Bond Cleavage and CC Bond Formation? A Theoretical Study. Issue 40 (20th August 2015)

• Record Type: Journal Article
• Authors: Ogawa, Hiroyuki; Minami, Hiroki; Ozaki, Takashi; Komagawa, Shinsuke; Wang, Chao; Uchiyama, Masanobu
• Is Part Of: Chemistry. Volume 21:Issue 40(2015)
• Page Start: 13904
• Page End: 13908
• Publication Date: 2015-08-20
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201502114
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Ni‐catalyzed cross‐coupling between aryl alkyl ethers (ArOR) and Grignard reagents (RMgBr), known since 1979, proceeds under mild conditions in many cases. Although the reaction routes of various synthetic protocols involving transition‐metal‐catalyzed CO bond activation have been elucidated, the mechanism of this etheric Kumada–Tamao–Curriu reaction remains enigmatic. This is because oxidative addition of inert etheric CO to Ni⁰ is thermodynamically and kinetically unfavorable, making it hard to explain the observed high reactivity of ether toward Ni catalysts. In this work, we used DFT calculations to identify a plausible reaction pathway by the Ni⁰‐ate complex, which enables smooth CO bond cleavage and R‐group transfer with reasonable activation barriers; this mechanism also accounts for the ineffectiveness of Pd catalysts. These results throw new light on both CO activation and cross‐coupling, and should be valuable for further rational development of the methodologies.</p> </abstract>