Reagent-free intramolecular hydrofunctionalization: a regioselective 6-endo-dig cyclization of o-alkynoylphenols. Issue 6 (28th February 2022)

• Record Type: Journal Article
• Authors: Jung, Chanhyun; Li, Siyuan; Lee, Kwanghee; Viji, Mayavan; Lee, Heesoon; Hyun, Soonsil; Lee, Kiho; Kang, Young Kee; Chaudhary, Chhabi Lal; Jung, Jae-Kyung
• Is Part Of: Green chemistry. Volume 24:Issue 6(2022)
• Page Start: 2376
• Page End: 2384
• Publication Date: 2022-02-28
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d1gc04848a
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Solvent-directed intramolecular hydrofunctionalization of readily available o -alkynoylphenols 1 was successfully achieved under reagent-free conditions. Abstract : Solvent-directed intramolecular hydrofunctionalization of readily available o -alkynoylphenols 1 was successfully achieved under reagent-free conditions. The hydrofunctionalization of 1 occurred by nucleophilic attack on the phenolic oxygen followed by consecutive migration of the phenolic H atom to the alkyne center, eventually affording γ-benzopyranones 2 . The phenol O–H group forms intramolecular H-bonds with the carbonyl group, and we predict that these H-bonds can be distorted into their most preferred conformation in the presence of polar solvents. A regioselective 6- endo-dig cyclization seems to be thermodynamically favoured over 5- exo-dig cyclization, as supported by DFT calculations. This strategy is remarkable because it is reagent-free, regioselective, highly atom economical, and highly atom, carbon and reaction mass efficient.