Abstract
The regio- and site-selective ring expansion of dienes and the regioselective ring expansion of substituted cyclopentenes provide 1,3-cycloheptadienes by enyne metathesis under methylene-free conditions. Site-selectivity results from differential ring strain among two different cycloalkenes in diene reactants. The high regioselectivity found in the ring expansion of tetrahydroindene (THI) is explained on the basis of a selective ring opening by the second generation Grubbs' ruthenium carbene complex. The ring opening of substituted cyclopentenes and cyclopentene contained in a bicyclic ring system was also achieved. The ring expansion of bicyclic dienes provided seven-membered dienes contained in the bicyclo[5.2.0]nonane ring system. Details of the structural analysis are also discussed. A mechanistic analysis is provided to account for the data presented herein.
Original language | English (US) |
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Pages (from-to) | 6909-6919 |
Number of pages | 11 |
Journal | Tetrahedron |
Volume | 64 |
Issue number | 29 |
DOIs | |
State | Published - Jul 14 2008 |
Keywords
- 1,3-Cycloheptadiene
- Enyne metathesis
- Grubbs' catalyst
- Regioselectivity
- Ring expansion
- Ring synthesis
- Site-selectivity
ASJC Scopus subject areas
- Biochemistry
- Drug Discovery
- Organic Chemistry