Intermolecular transition metal-catalyzed [4 + 2 + 2] cycloaddition reactions: a new approach to the construction of eight-membered rings.
Transition metal-catalyzed cycloaddition reactions represent powerful methods for the construction of complex polycyclic systems. We have developed a new intermolecular metal-catalyzed [4 + 2 + 2] cycloaddition of heteroatom-tethered enyne derivatives with 1,3-butadiene. This study demonstrates that excellent selectivity can be obtained for the heterocycloaddition adducts through the judicious choice of silver salt. The development of the tandem rhodium-catalyzed allylic substitution [4 + 2 + 2] cycloaddition provides a convenient three-component coupling that circumvents the prior formation of the enyne derivative. Finally, the introduction of a stereogenic center at C-2 leads to a diastereoselective cycloaddition, which provides a powerful new method for the construction of bicyclic octanoid ring systems applicable to target directed synthesis.
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA. paevans@indiana.edu
P Andrew
PA
Evans
John E
JE
Robinson
Erich W
EW
Baum
Aleem N
AN
Fazal
D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis*; D009795:Octanes / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry
D001643:Bridged Bicyclo Compounds; D009795:Octanes; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; C016305:chlorotris(triphenylphosphine)rhodium; D012238:Rhodium