DFT Study on Rhodium(III)-Catalyzed Redox-Neutral [3 + 2] Cyclization of Sulfoxonium Ylides with Alkynes: Mechanism
Yugui Qiu1, Zhenfeng Shang2, Xiufang Xu2
1College of Chemistry and Environmental Science, Laboratory of Xinjiang Native Medicinal and Edible Plant Resources Chemistry, Kashi University, Kashi 844000, China.
None:
The [3 + 2] cycloaddition mechanism of the rhodium-catalyzed redox-neutral cyclization of sulfoxonium ylides with 1,4-diphenyl-1,3-butadiyne has been investigated using density functional theory. The calculations indicate that the active catalyst is [Cp*Rh(OAc)2]. The reaction proceeds sequentially through C(sp2)-H bond cleavage, alkyne insertion into the Rh-C(sp2) bond, intramolecular nucleophilic addition, protodemetalation, and stepwise proton migration, ultimately affording the product 3-phenyl-2-(phenylethynyl)-1-indenone. Additionally, based on the computational results, we propose that the rate-determining step of the catalytic cycle is governed by both C-H activation and intramolecular nucleophilic addition, rather than being controlled by a single step alone.
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