Photochemical Transformations of Some Neoclerodane and Labdane Diterpene Ketones

✍ Scribed by Gianfranco Fontana; Giuseppe Savona; Nicolò Vivona; Benjamín Rodríguez

• Book ID: 101280153
• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 149 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199909)1999:9<2011::aid-ejoc2011>3.0.co;2-#

✦ Synopsis

transformed into 7 by a stereoselective intramolecular [2+2] cycloaddition reaction involving its furanic 13(16)-double Some neoclerodane (2-4) and labdane (5 and 6) diterpene ketones having a β-or γ-hydroxy function, an α-epoxy group, bond. Finally, the α-epoxy ketone 6 was rearranged to the 10(9Ǟ8)abeo-labda-7,9-dione derivative 10. Apart from the or an α-olefinic double bond have been irradiated at λ = 313 nm in dry solvents (benzene or methanol). Fruticolone (2) interest in these reactions for synthetic purposes, the photochemical transformation of fruticolone (2) into yielded the naturally occurring 5,6-seco-neoclerodan-6,1αolide derivative fruticolide (1), while hispanolone (5) gave fruticolide (1) suggests that the latter might originate from the former as an artefact during the extraction and isolation the δ-lactone 8, both transformations involving a Norrish type I photoreaction. The α,β-unsaturated ketone derivative 4 was procedure, rather than from any biogenetic pathway.