Ring Synthesis by Stereoselective, Methylene-Free Enyne Cross Metathesis
摘要:
Tandem enyne metathesis between 1-alkynes and 1,5-cyclooctadiene or all-cis-1,4-polybutadiene resulted in a direct, one-step ring synthesis of cyclohexadienes by methylene-free metathesis. The use of methylene-free metathesis conditions provided apparent Z-selectivity in the intermolecular enyne metathesis step.
Pd-Catalyzed Asymmetric Allylic Etherification Using Chiral Biphenol-Based Diphosphinite Ligands and Its Application for The Formal Total Synthesis of (−)-Galanthamine
作者:Yang Zang、Iwao Ojima
DOI:10.1021/jo400355j
日期:2013.4.19
A library of novelchiral biphenol-based diphosphinite (BOP) ligands was designed and created. These BOP ligands were applied to a Pd-catalyzed intermolecular allylic etherification reaction, which provided a key intermediate for the formaltotalsynthesis of (−)-galanthamine with 97% ee in 97% yield.
Synthesis of 1,3-cyclohexadienes by tandem diene–alkyne metathesis: improved procedure
作者:Mark D. Middleton、Steven T. Diver
DOI:10.1016/j.tetlet.2005.04.017
日期:2005.6
A practical synthesis of 2-substituted 1,3-cyclohexadienes by the cross enyne metathesis between alkynes and 1,5-hexadiene is reported. The isolation of the 1,3-cyclohexadienes has been hampered by the formation of an inseparable triene by-product. The use of a second consecutive cross alkene metathesis to give water-soluble products allowed removal of this by-product. Using this one-pot procedure, a synthesis of cyclohexadienes from simple starting materials was developed. The procedure was used in a three-step synthesis of a functionalized tetrahydroquinoline using Pd(II)-catalyzed chloroacetoxyiation (Backvall reaction) for cyclohexadiene functionalization. (c) 2005 Elsevier Ltd. All rights reserved.
2-SUBSTITUTED-1,3-CYCLOHEXADIENES BY INTERMOLECULAR, METHYLENE-FREE TANDEM ENYNE METATHESIS
作者:Kulkarni, Amol A、Diver, Steven T.、Shibasaki, Masakatsu、Maki, Keisuke