Roldan BJ, Hammerstad TA, Galliher MS, Keylor MH, Pratt DA, Stephenson CRJ. Leveraging the Persistent Radical Effect in the Synthesis of trans-2,3-Diaryl Dihydrobenzofurans.
Angew Chem Int Ed Engl 2023;
62:e202305801. [PMID:
37390358 PMCID:
PMC10528744 DOI:
10.1002/anie.202305801]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/23/2023] [Accepted: 06/29/2023] [Indexed: 07/02/2023]
Abstract
A simple method for accessing trans-2,3-diaryl dihydrobenzofurans is reported. This approach leverages the equilibrium between quinone methide dimers and their persistent radicals. This equilibrium is disrupted by phenols that yield comparatively transient phenoxyl radicals, leading to cross-coupling between the persistent and transient radicals. The resultant quinone methides with pendant phenols rapidly cyclize to form dihydrobenzofurans (DHBs). This putative biomimetic access to dihydrobenzofurans provides superb functional group tolerance and a unified approach for the synthesis of resveratrol-based natural products.
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