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Sun W, Kayal S, Raimbach WAT, Sun XZ, Light ME, Hanson-Heine MWD, George MW, Harrowven DC. Wavelength dependent photoextrusion and tandem photo-extrusion reactions of ninhydrin bis-acetals for the synthesis of 8-ring lactones, benzocyclobutenes and orthoanhydrides. Chem Commun (Camb) 2022; 58:1546-1549. [PMID: 35014645 DOI: 10.1039/d1cc06800h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ninhydrin bis-acetals give access to 8-ring lactones, benzocyclo-butenes and spirocyclic orthoanhydrides through photoextrusion and tandem photoextrusion reactions. Syntheses of fimbricalyxlactone B, isoshihunine and numerous biologically-relevant heterocycles show the value of the methods, while TA-spectroscopy and TD-DFT studies provide mechanistic insights on their wavelength dependence.
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Affiliation(s)
- Wei Sun
- Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Surajit Kayal
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | | | - Xue-Zhong Sun
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Mark E Light
- Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | | | - Michael W George
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK.,Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315100, China
| | - David C Harrowven
- Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
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Abstract
A total synthesis of the aglycone of IB-00208 was accomplished in 22 steps using a newly developed approach towards polycyclic 1,4-dioxygenated xanthones from benzocyclobutenones. The generality of this entry to xanthones was initially established on several model systems before it was successfully applied to the construction of the hexacyclic core of the natural product. A new and potentially general approach towards angularly-fused benzocyclobutenones using ring-closing metathesis (RCM) was also developed.
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