scholarly journals Metathesis Transformations of Natural Products: Cross-Metathesis of Natural Rubber and Mandarin Oil by Ru-Alkylidene Catalysts

Molecules ◽  
2012 ◽  
Vol 17 (5) ◽  
pp. 6001-6010 ◽  
Author(s):  
Araceli Martínez ◽  
Selena Gutiérrez ◽  
Mikhail A. Tlenkopatchev
Keyword(s):  
Natural Products ◽  
Natural Rubber ◽  
Cross Metathesis

ChemInform Abstract: Cross-Metathesis in Natural Products Synthesis

ChemInform ◽  
2011 ◽  
Vol 42 (17) ◽  
pp. no-no
Author(s):  
Joelle Prunet ◽  
Laurence Grimaud
Keyword(s):  
Natural Products ◽  
Cross Metathesis ◽  
Natural Products Synthesis

scholarly journals The allylic chalcogen effect in olefin metathesis

2010 ◽  
Vol 6 ◽  
pp. 1219-1228 ◽  
Author(s):  
Yuya A Lin ◽  
Benjamin G Davis
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Olefin Metathesis ◽  
Chemical Biology ◽  
Positive Influence ◽  
Efficient Synthesis ◽  
Cross Metathesis ◽  
Allyl Sulfide ◽  
Hydroxy Groups ◽  
Allyl Sulfides

Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications.

scholarly journals A Natural Rubber Waste Derived Surfactant for High Internal Phase Emulsion Templating of Poly(dicyclopentadiene)

2021 ◽  
Author(s):  
Viktor Schallert ◽  
Christian Slugovc
Keyword(s):  
Natural Rubber ◽  
Ring Opening ◽  
Ester Group ◽  
Ionic Surfactants ◽  
Ionic Surfactant ◽  
High Internal Phase Emulsion ◽  
Cross Metathesis ◽  
Rubber Waste ◽  
Internal Phase ◽  
Emulsion Templating

The use of a surfactant derived from the degradation of natural rubber gloves via cross-metathesis with methyl acrylate and subsequent saponification of the ester group for the stabilization of water in dicyclopentadiene high internal phase emulsions is described. The versatility of the resulting high internal phase emulsion was demonstrated by polymerizing the continuous dicyclopentadiene phase via Ring-opening Metathesis Polymerization yielding macroporous poly(dicyclopentadiene) foams with a porosity of 82 %. The use of the ionic surfactant allows for the preparation of foams, which are resistant to absorb water. This property was hitherto not accessible with protocols involving the use of non-ionic surfactants commonly employed in emulsion templating of polymers.<br>

scholarly journals A Natural Rubber Waste Derived Surfactant for High Internal Phase Emulsion Templating of Poly(dicyclopentadiene)

2021 ◽  
Author(s):  
Viktor Schallert ◽  
Christian Slugovc
Keyword(s):  
Natural Rubber ◽  
Ring Opening ◽  
Ester Group ◽  
Ionic Surfactants ◽  
Ionic Surfactant ◽  
High Internal Phase Emulsion ◽  
Cross Metathesis ◽  
Rubber Waste ◽  
Internal Phase ◽  
Emulsion Templating

The use of a surfactant derived from the degradation of natural rubber gloves via cross-metathesis with methyl acrylate and subsequent saponification of the ester group for the stabilization of water in dicyclopentadiene high internal phase emulsions is described. The versatility of the resulting high internal phase emulsion was demonstrated by polymerizing the continuous dicyclopentadiene phase via Ring-opening Metathesis Polymerization yielding macroporous poly(dicyclopentadiene) foams with a porosity of 82 %. The use of the ionic surfactant allows for the preparation of foams, which are resistant to absorb water. This property was hitherto not accessible with protocols involving the use of non-ionic surfactants commonly employed in emulsion templating of polymers.<br>

Relay Cross Metathesis for the Ascent of the Terpenoids

2019 ◽  
Author(s):  
Karim Bahou ◽  
D. Christopher Braddock ◽  
Adam G. Meyer ◽  
G. Paul Savage ◽  
Zhensheng Shi
Keyword(s):  
Natural Products ◽  
Building Blocks ◽  
Design And Implementation ◽  
Cross Metathesis ◽  
Naturally Occurring

We report the design and implementation of a relay cross metathesis (ReXM) reaction for the ascent of the terpenoids in an iterative protocol using naturally occurring terpenoid building blocks. The method is used for the synthesis of a diterpene-benzoate macrolide of biogenetic relevance to the bromophycolide family of natural products.

Synthesis of Unsaturated Esters by Cross-Metathesis of Terpenes and Natural Rubber Using Ru-Alkylidene Catalysts

2019 ◽  
Vol 23 (12) ◽  
pp. 1356-1364
Author(s):  
Araceli Martínez ◽  
Mikhail A. Tlenkopatchev ◽  
Selena Gutiérrez ◽  
Manuel Burelo ◽  
Joel Vargas ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Unsaturated Ester ◽  
Low Molecular Weight ◽  
Diethyl Maleate ◽  
Metathesis Reaction ◽  
Unsaturated Esters ◽  
Cross Metathesis ◽  
Dimethyl Maleate ◽  
The Cross ◽  
Low Activity

This study reports the cross-metathesis of bicyclic &#946;-pinene, acyclic cis-3- methylpent-2-ene terpenes and the natural rubber with functionalized olefins, a route for the functionalization of the carbon-carbon double bond of natural products to obtain aliphatic unsaturated esters. The production of unsaturated esters from &#946;-pinene and cis-3- methylpent-2-ene via cross-metathesis reaction with dimethyl maleate and diethyl maleate in the presence of the ruthenium-alkylidene [Ru(Cl)2(=CHPh)(1,3-bis(2,4,6- trimethylphenyl)-2-imidazolidinylidene)(PCy3)] (I), [Ru(Cl)2(=CH(o-isopropoxyphenylmethylene))( 1,3-bis(2,4,6-trimethylphenyl) -2-imidazolidinylidene)] (II) and rutheniumvinylidene [RuCl2(=C=CH(p-C6H4CF3))(PCy3)2] (III) was carried out. Results showed that the reaction of &#946;-pinene with diethyl maleate using II catalyst produced unsaturated esters with 43 % selectivity. I and III catalysts showed low activity toward the cross-metathesis of &#946;-pinene and dimethyl maleate. A survey about the cross-metathesis of acyclic cis-3-methylpent-2-ene with diethyl maleate by II catalyst was also studied. The formation of ethyl but-2-enoate and ethyl-3-methylpent-2-enoate products was highly selective by 63 %. The unsaturated esters formation from the cross-metathesis degradation of natural rubber (99.9 % cis-polyisoprene) with dimethyl maleate and diethyl maleate using I-III catalysts was accomplished as well. I and II catalysts showed high activity in the degradation of natural rubber with diethyl maleate to produce the low molecular weight of oligomers unsaturated ester products (Mn = 1 x 103 g mol-1) with isoprene units of m = 10 – 27 and yields ranging from 68 to 94 %.

Sign in / Sign up

Export Citation Format

Share Document