Synthetic Studies on Lycopodium Alkaloid, Magellanine: Stereoselective Construction of Functionallized Angular Tricyclic Skeletons by Intramolecular Pauson–Khand Reaction
作者:Miyuki Ishizaki、Yuka Niimi、Osamu Hoshino
DOI:10.1246/cl.2001.546
日期:2001.6
Angular tricyclic compounds as intermediates for total synthesis of magellanine were synthesized by stereoselective Ireland–Claisen rearrangement and intramolecular Pauson–Khand reaction of exo-methylenecyclohexylalkynes. Interestingly, remarkably different reactivity was observed in the Pauson–Khand reaction of cis- and trans-disubstituted exo-methylenecyclohexylalkynes.
Abstract An efficient nucleophilic allylic substitution of a variety of Morita–Baylis–Hillman adducts with enamines catalyzed by Pd(OAc)2 in the presence of ZnBr2 as a promoter is described in the present study. The reaction gives SN2-type 1,5-dicarbonyl compounds that may subsequently undergo an intramolecular conjugate addition onto the enone moiety affording the corresponding 1,4-adducts. All the
An Efficient One Pot Synthesis of Bicyclic Dienones
作者:Farhat Rezgui、Mohamed Moncef El Gaïed
DOI:10.1039/a902012h
日期:——
Bicyclic dienones 4 are prepared in a one pot process from the reaction of 2-(acetoxymethyl)cyclohex-2-enone 1 with 1,3-dicarbonyl compounds 2 in the presence of K2CO3 in refluxing absolute ethanol.
DMAP- or imidazole-mediated clean and rapid conversion of cyclic Morita–Baylis–Hillman (MBH) acetates into the corresponding γ-keto allyl phosphonates in 70–93% yields is described herein. This allylic nucleophilic substitution works well with primary and secondary acetates bearing, at the β′-position, linear or branched alkyl groups and aryl groups.