ORGN 893 |
| gem-Dichlorocyclopropanes substituted with alkenyl and silyloxy groups are readily accessible from reaction of dichlorocarbene with 2-silyloxy-1,3-dienes (Scheme 1). When subjected to thermal or Lewis acidic conditions, these substrates undergo the known disrotatory 2π electrocyclic opening to furnish pentadienyl cations. When silver(I) is used, the pentadienyl species then undergo a Nazarov-type electrocyclization, providing chlorocyclopentenones in good to excellent yields. Thus, this two-step sequence functions as an equivalent to the Nazarov cyclization under mild conditions and without proceeding through the usual 1,4-diene-3-one precursors. Preliminary results of this study will be presented, along with recent examples involving trapping of the cyclopentenyl cation intermediate with pendant nucleophiles to furnish complex, polycyclic products.
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New Reactions and Methodology
8:00 AM-11:40 AM, Thursday, 14 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |
