Formal intermolecular 4 + 4 approach to cyclooctanoids: 4 + 3 capture of the Nazarov oxyallyl intermediate with simple 1,3-dienes.
[reaction: see text] Simple 1,4-dien-3-ones and 1,3-dienes react in the presence of BF(3).OEt(2) via a domino Nazarov electrocyclization/intermolecular [4 + 3]-cycloaddition sequence to furnish keto-bridged cyclooctenes in good yield. Most cases showed high diastereofacial selectivity and/or endo/exo selectivity, and surprising levels of regioselectivity were observed when isoprene was used as the diene partner.
Wang
Yong
Y
Department of Chemistry, University of Utah, 315 S. 1400 East, Rm. 2020, Salt Lake City, Utah 84112-0850, USA.
Schill
Brenden D
BD
Arif
Atta M
AM
West
F G
FG
D000466:Alkadienes / Q000737:chemistry*; D000498:Allyl Compounds / Q000737:chemistry*; D003500:Cyclization; D034242:Cyclooctanes / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D006844:Hydrocarbons, Cyclic / Q000737:chemistry; D013237:Stereoisomerism
D000466:Alkadienes; D000498:Allyl Compounds; D034242:Cyclooctanes; D006844:Hydrocarbons, Cyclic