scholarly journals Primary Anion–π Catalysis of Epoxide‐Opening Ether Cyclization into Rings of Different Sizes: Access to New Reactivity

2020 ◽  
Vol 132 (15) ◽  
pp. 6332-6336 ◽  
Author(s):  
Miguel Paraja ◽  
Stefan Matile
Keyword(s):  
Epoxide Opening ◽  
Primary Anion

An Endo ‐Selective Epoxide‐Opening Cascade for the Fast Assembly of the Polycyclic Core Structure of Marine Ladder Polyethers

2020 ◽  
Vol 59 (42) ◽  
pp. 18473-18478
Author(s):  
Feng‐Xing Li ◽  
Shu‐Jian Ren ◽  
Pei‐Fang Li ◽  
Peng Yang ◽  
Jin Qu
Keyword(s):  
Core Structure ◽  
Epoxide Opening

Chemical Diversity of Volatile Macrocylic Lactones from Frogs

Synlett ◽  
2021 ◽  
Author(s):  
Stefan Schulz ◽  
Dennis Poth ◽  
Pardha Saradhi Peram ◽  
Susann Hötling ◽  
Markus Menke ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Chemical Diversity ◽  
Synthetic Methods ◽  
Epoxide Opening ◽  
Scientific Approach ◽  
Long Time ◽  
Fatty Acid Biosynthetic Pathway ◽  
Unsaturated Lactones ◽  
Male Specific ◽  
Synthetic Approaches

AbstractFor a long time, frogs were believed to communicate primarily via the acoustic channel, but during the last decades it became obvious that various lineages also use chemical communication. In this Account we present our research on the identification of volatile lactones from Madagascan Mantellidae and African Hyperoliidae frogs. Both possess male specific glands that can disseminate a range of volatile compounds. Key constituents are macrocyclic lactones. They show high variability in structure and occurrence. We focus here on the synthetic approaches we have used to clarify constitution and configuration of the glandular compounds. Key synthetic methods are ring-closing metathesis and nucleophilic epoxide opening. Often, but not always, the natural compounds occurs in amounts that excludes their investigation by NMR spectroscopy. Instead, we use GC/MS analysis, GC/IR, microreactions, and synthesis to identify such components. Several aspects of our work will be described giving some insight in our scientific approach.1 Introduction2 Macrocylic Lactones from the Fatty Acid Biosynthetic Pathway3 Unsaturated Lactones4 Terpenoid Lactones5 Macrolide Occurrence6 Conclusions

General synthesis of carbanucleosides via regiospecific epoxide opening by the aglycone

1991 ◽  
Vol 32 (5) ◽  
pp. 611-614 ◽  
Author(s):  
Harald Baumgartner ◽  
Christoph Marschner ◽  
Rainer Pucher ◽  
Herfried Griengl
Keyword(s):  
Epoxide Opening ◽  
General Synthesis

γ- and δ-epoxy sulfones. Formation of different ring-sized products upon reaction with CH3MgI or LiN[CH(CH3)2]2

1981 ◽  
Vol 59 (10) ◽  
pp. 1415-1424 ◽  
Author(s):  
John M. Decesare ◽  
Bernard Corbel ◽  
Tony Durst ◽  
John F. Blount
Keyword(s):  
Structure Determination ◽  
Grignard Reagent ◽  
Lithium Diisopropylamide ◽  
X Ray ◽  
Iodide Ion ◽  
Epoxide Opening ◽  
Cyclobutane Ring

γ-Epoxy sulfones in which the epoxide function is terminal yield cyclopropylmethanol derivatives on reaction with methyllithium or lithium diisopropylamide. In contrast, treatment of these epoxides with two equivalents of CH3MgI gives only cis-3-phenylsulfonylcyclobutanols. The cis-relationship between the OH and sulfonyl groups was proven in one instance by an X-ray structure determination. Internal γ-epoxy sulfones yield cyclopropylmethanols with all bases studied. All δ-epoxy sulfones studied furnished cis-3-phenylsulfonylcyclopentanols upon reaction with the Grignard reagent. These same epoxides gave either cyclopentanols or noncyclic products upon reaction with LDA; no cyclobutane ring containing products were obtained contrary to the expectations based on Stork's results with the corresponding epoxy nitriles (ref. 2). The mechanism of the Grignard-mediated reaction involves epoxide opening by iodide ion, α-sulfonyl Grignard formation, and, finally, cyclization. When LDA or CH3Li is used the products are formed by an intramolecular SN2 opening of the epoxide by an α-lithio sulfone.

Mechanism of Titanocene-Mediated Epoxide Opening through Homolytic Substitution

2007 ◽  
Vol 129 (5) ◽  
pp. 1359-1371 ◽  
Author(s):  
Andreas Gansäuer ◽  
Andriy Barchuk ◽  
Florian Keller ◽  
Martin Schmitt ◽  
Stefan Grimme ◽  
...  
Keyword(s):  
Epoxide Opening ◽  
Homolytic Substitution

ChemInform Abstract: Water Overcomes Methyl Group Directing Effects in Epoxide-Opening Cascades.

ChemInform ◽  
2009 ◽  
Vol 40 (40) ◽  
Author(s):  
Christopher J. Morten ◽  
Timothy F. Jamison
Keyword(s):  
Methyl Group ◽  
Epoxide Opening
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