The development of more efficient syntheses of polycyclic diterpenes through intramolecular cyclopropanation of aryl rings in diazomethyl ketones

Autor:	Jonathan C. Morris, Barbara Frey, Friedrich-Wilhelm Russkamp, Lewis N. Mander, Daniel Harry Rogers, G. R. King, Francis S. Roden, R. A. Bell
Rok vydání:	1996
Předmět:	chemistry.chemical_compound chemistry Cyclopropanation Stereochemistry General Chemical Engineering Intramolecular force Aryl Total synthesis Moiety General Chemistry Tropone Ring (chemistry) Cycloaddition
Zdroj:	Pure and Applied Chemistry. 68:515-522
ISSN:	1365-3075 0033-4545
DOI:	10.1351/pac199668030515
Popis:	Several approaches to the total synthesis of the troponoid diterpene lactone 1 have been undertaken. The most successful approach to date has afforded secoharringtonolide 26. The intramolecular cyclopropanation reaction of an aryl ring by means of the transition metal catalysed reaction of a diazoacetyl function was used to assemble the 5h' ring system and to provide a cycloheptatrienyl precursor to the tropone moiety. In a cognate study, the intramolecular cyclopropanation reactions of the aromatic ring in a wide range of tetralin 2-diazomethyl ketones afforded norcaradiene products which, because of geometric constraints, were energetically more favoured than the tautomeric cycloheptatrienes. The (4+2) cycloaddition of selected dienophiles to some of these products, e.g. the vinyl analogue 34, allowed the rapid stereocontrolled assembly of advanced intermediates for the synthesis of diterpenoids 2 and 3.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::416a4c0efcfa6e8d6ca488d8f99a3b4c https://doi.org/10.1351/pac199668030515 Zobrazit plný text záznamu