A novel synthesis of fluorine-containing cyclopentenones via Pauson-Khand reaction

Intermolecular Pauson-Khand reaction of fluoroalkylated alkynes with 2-norbornene or 2,5-norbornadiene at the reflux temperature of dichloroethane proceeded smoothly to give the corresponding cyclopentenone derivatives in high yields as a mixture of regioisomers. On the other hand, intramolecular Pauson-Khand reaction of fluorine-containing 1,6-enyne proceeded in the presence of NMO or TMANO to give the bicyclic adducts in good yields. Additionally, allyl CF3-propargyl ether also underwent a smooth Pauson-Khand reaction in the presence of amine oxide, the corresponding bicyclic compounds being obtained in a highly diastereoselective manner. (C) 2012 Elsevier B.V. All rights reserved.