title: Pd-catalyzed cycloisomerization of 4-aza-1,6-enynes to 3-aza-bicyclo[4.1.0]hept-2-enes.
abstract: A method for the synthesis of bicyclo[4.1.0]heptenes from 1,6-enynes through Pd-catalyzed cycloisomerization has been developed. N- and O-tethered 1,6-enynes were successfully transformed to their corresponding 3-aza- and 3-oxabicyclo[4.1.0]heptenes in reasonable-to-high yields using the catalysts [PdCl2(CH3CN)2]/P(OPh)3 or [Pd(maleimidate)2(PPh3)2] in toluene. The computational calculations using density functional theory indicate that [PdCl2{P(OPh)3}] in the oxidation state Pd(II) acts as the active catalyst species for the formation of 3-azabicyclo[4.1.0]heptenes through 6-endo-dig cyclization.
authors: Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-747 (Korea).
authors: Hye Mi
authors: HM
authors: Oh
authors: Ji Eun
authors: JE
authors: Park
authors: Jisu
authors: J
authors: Kim
authors: Ju Hyun
authors: JH
authors: Kim
authors: Youn K
authors: YK
authors: Kang
authors: Young Keun
authors: YK
authors: Chung
keywords: cyclization; density functional theory; enynes; isomerization; palladium