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Updated: Oct 8, 2025
A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
Medium and Large N-Heterocycle Formation via Allene Hydroamination with a Bimetallic Rh(II) Catalyst
Kelton G Forson1, Benjamin O Bohman1, Coriantumr Z Wayment1
1Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States.
Abstract:
We report the synthesis of a 2-phosphinoimidazole-derived bimetallic Rh(II) complex that enables intramolecular allene hydroamination to form 7- to 10-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of various N-heterocycles. Macrocyclizations that form 11- to 15-member N-heterocycles are also demonstrated. Mechanistic studies suggest that the reaction proceeds via reversible allene insertion with a Rh-hydride followed by C-N bond-forming reductive elimination. We hypothesize that the reactivity observed with our catalyst vs monometallic Rh complexes is derived from the bimetallic nature of our complex.
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