Lithium Hydroxide Assisted Endo‐Selective [4+4]‐Photocycloaddition of Pyran‐2‐ones. Issue 16 (9th April 2021)

• Record Type: Journal Article
• Authors: Li, Lei; Turnbull, William L.; McDonald, Robert; West, F. G.
• Is Part Of: European journal of organic chemistry. Issue 16(2021)
• Page Start: 2294
• Page End: 2300
• Publication Date: 2021-04-09
• Subjects: Alkali metals -- Chelates -- Cycloaddition -- Heterocycles -- Photochemistry; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202100122
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: 3‐Acyl‐4‐hydroxypyan‐2‐ones with pendent furans, readily available from dehydroacetic acid, are substrates for intramolecular [4+4]‐photocycloaddition. In the presence of stoichiometric lithium base, these substrates undergo conversion to lactone‐bridged cyclooctenones in moderate to good yields upon irradiation in THF at 0 °C. In contrast to other crossed [4+4]‐photocycloadditions of pyran‐2‐ones, these examples proceed with complete diastereoselectivity for the endo cycloadducts. Abstract : Readily accessible 3‐acyl‐4‐hydroxypyran‐2‐ones with pendent furans undergo [4+4]‐photocycloaddition reactions in the presence of lithium ion to afford lactone‐bridged cyclooctenones with complete selectivity for the endo cycloadducts.