Enone construction: A silver‐mediated olefin acylation reaction is described, in which five‐, six‐, and ‐seven‐membered rings, tetrasubstituted olefins, bridged bicycles, spirocycles, and benzoxepinones are prepared. Highly selective intermolecular reactions are coupled to a Nazarov cyclization for the effective preparation of cyclopentenones, including the core of modhephene (see scheme).
Alkene-allenecyclopropane radical cyclisations promoted by tris-(trimethylsilyl)silane
作者:Nigel R. Jones、Gerald Pattenden
DOI:10.1016/j.tetlet.2009.03.024
日期:2009.7
butenyl-substituted allenecyclopropanes 5 and 12 with tris-(trimethylsilyl)silane (TTMSS)–AIBN results in facile radical cyclisations into the cyclopropane-carbon centres of the allene moieties, followed by cyclopropane ring-opening and alleneisomerisation, leading to the bicyclic 1,3-dienes 10 and 13, respectively. By contrast, treatment of the pentenyl-substituted allenecyclopropane 15a and the iodoethane 18 with