Cover Feature: Lithium Hydroxide Assisted Endo‐Selective [4+4]‐Photocycloaddition of Pyran‐2‐ones (Eur. J. Org. Chem. 16/2021). Issue 16 (20th 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: 2254
• Page End: 2254
• Publication Date: 2021-04-20
• 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.202100458
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : The Cover Feature shows the light‐driven intramolecular [4+4]‐cycloaddition reaction of pyran‐2‐ones with 3‐acyl side‐chains terminated with furans. Irradiation at 0 °C in the presence of 1 equivalent of LiOHH2 O and sparteine cleanly converts these linked heterocycles into lactone‐bridged cyclooctenones with complete endo selectivity. A mechanistic rationale involving a templating effect by lithium cation can explain the observed stereoselectivity, which is the opposite to what is seen in other pyran‐2‐one [4+4]‐photocycloadditions. More information can be found in the Full Paper by F. G. West et al.