title: Intermolecular rhodium-catalyzed [3+2+2] carbocyclization of alkenylidenecyclopropanes with activated alkynes: regio- and diastereoselective construction of cis-fused bicycloheptadienes.
abstract: Polycyclic structures that contain seven-membered carbocycles constitute important structural motifs that are ubiquitous in several classes of bioactive natural products. We have developed the first regio- and diastereoselective intermolecular rhodium-catalyzed [3+2+2] carbocyclization of carbon- and heteroatom-tethered alkenylidenecyclopropanes with mono- and disubstituted alkynes for the construction of cis-fused bicycloheptadienes. This study delineates some of the critical features for controlling regioselectivity in this process and demonstrates that E-alkenes can be incorporated in a stereospecific manner to afford products with up to three new stereogenic centers. The latter feature is particularly significant given that related carbocyclization reactions are often limited in this respect.
authors.affiliation: Department of Chemistry, The University of Liverpool, Liverpool, L69 7ZD, UK. Andrew.Evans@liverpool.ac.uk
authors.forename: P Andrew
authors.initials: PA
authors.lastname: Evans
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Inglesby
mesh_terms: D000466:Alkadienes / Q000138:chemical synthesis / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis*; D002384:Catalysis; D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry*; D006536:Heptanes / Q000138:chemical synthesis*; D012238:Rhodium / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000466:Alkadienes; D000480:Alkynes; D001643:Bridged Bicyclo Compounds; D003521:Cyclopropanes; D006536:Heptanes; D012238:Rhodium