Complete Stereocontrol in the Synthesis of Harmonine and Novel Analogues Facilitated by a Grubbs Z-Selective Cross-Metathesis Catalyst

2015 ◽  
Vol 68 (12) ◽  
pp. 1815 ◽  
Author(s):  
Steven-Alan G. Abel ◽  
Wesley J. Olivier ◽  
Richard L. Pederson ◽  
Alex C. Bissember ◽  
Jason A. Smith
Keyword(s):  
The Self ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Metathesis Catalyst ◽  
The Cross

(R)-Harmonine was synthesised in 15 % overall yield via a six-step sequence exploiting a Z-selective cross-metathesis reaction as its centrepiece. By this strategy, the cis-olefin present in the target could be installed exclusively. The use of an alcohol and an ester as the amine precursors was crucial for isolating the cross-metathesis product from the self-metathesis products. This method was also used to prepare two novel analogues of harmonine.

Regulation of the degree of blockiness of the norbornene–cyclooctene copolymer synthesized via the cross-metathesis reaction

2016 ◽  
Vol 58 (3) ◽  
pp. 292-297 ◽  
Author(s):  
Yu. I. Denisova ◽  
M. L. Gringolts ◽  
L. B. Krentsel’ ◽  
G. A. Shandryuk ◽  
A. D. Litmanovich ◽  
...  
Keyword(s):  
Metathesis Reaction ◽  
Cross Metathesis ◽  
The Cross

scholarly journals Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

2015 ◽  
Vol 11 ◽  
pp. 1392-1397 ◽  
Author(s):  
Ivan Šnajdr ◽  
Kamil Parkan ◽  
Filip Hessler ◽  
Martin Kotora
Keyword(s):  
Metathesis Reaction ◽  
Simple Method ◽  
Cross Metathesis ◽  
Terminal Alkenes ◽  
The Cross

Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl C-deoxyribosides was also developed. In addition, feasibility of deprotection and further transformations were briefly explored.

Ruthenium-catalyzed cross-metathesis with electron-rich phenyl vinyl sulfide enables access to 2,3-dideoxy-d-ribopyranose ring system donors

RSC Advances ◽  
2014 ◽  
Vol 4 (38) ◽  
pp. 19794-19799 ◽  
Author(s):  
Omar Boutureira ◽  
M. Isabel Matheu ◽  
Yolanda Díaz ◽  
Sergio Castillón
Keyword(s):  
Microwave Irradiation ◽  
Ring System ◽  
Metathesis Reaction ◽  
Vinyl Sulfide ◽  
Cross Metathesis ◽  
The Cross ◽  
Flexible Metal ◽  
Phenyl Vinyl

Microwave irradiation effectively accelerates the cross-metathesis reaction of 2-deoxy-d-ribose hydroxyalkene and derivatives with electron-rich phenyl vinyl sulfide using commercially available ruthenium-based catalysts, thus providing a flexible metal-mediated route to 2,3-dideoxy-d-ribopyranose ring system donors.

Study of the Cross-Metathesis Reaction of α-Hydroxy β,γ-Unsaturated Amides towards a Rapid and Flexible Total ­Synthesis of Symbioramide and its Isomer

Synlett ◽  
2017 ◽  
Vol 29 (02) ◽  
pp. 230-234 ◽  
Author(s):  
Alexandre Gratais ◽  
Samir Bouzbouz
Keyword(s):  
Methyl Ester ◽  
Total Synthesis ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Metathesis Reactions ◽  
The Cross

The reactivity of novel α-hydroxy β,γ-unsaturated amides in cross-metathesis reactions was extensively studied and used to perform a short total synthesis of symbioramide and its isomer from ­l-serine methyl ester.

scholarly journals 1H NMR Analysis of the Metathesis Reaction between 1-Hexene and (E)-Anethole Using Grubbs 2nd Generation Catalyst: Effect of Reaction Conditions on (E)-1-(4-Methoxyphenyl)-1-hexene Formation and Decomposition

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1483
Author(s):  
Marthinus Rudi Swart ◽  
Charlene Marais ◽  
Elizabeth Erasmus
Keyword(s):  
1H Nmr ◽  
Maximum Concentration ◽  
Metathesis Reaction ◽  
Reaction Conditions ◽  
2Nd Generation ◽  
Cross Metathesis ◽  
First Order Kinetics ◽  
Different Temperatures ◽  
The Cross ◽  
Catalyst Effect

The metathesis of 1-hexene and (E)-anethole in the presence of Grubbs 2nd generation catalyst was monitored by in situ 1H NMR spectroscopy at different temperatures (15 °C, 25 °C, and 45 °C) and anethole mol fractions (XAnethole ≈ 0.17, 0.29, 0.5, 0.71, 0.83). Time traces confirmed the instantaneous formation of (E)-1-(4-methoxyphenyl)-1-hexene, the cross-metathesis product. A maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene is reached fairly fast (the time depending on the reaction conditions), and this is followed by a decrease in the concentration of (E)-1-(4-methoxyphenyl)-1-hexene due to secondary metathesis. The maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene was more dependent on the XAnethole than the temperature. The highest TOF (3.46 min−1) was obtained for the reaction where XAnethole was 0.16 at 45 °C. The highest concentration of the cross-metathesis product was however achieved after 6 min with an anethole mol fraction of 0.84 at 25 °C. A preliminary kinetic study indicated that the secondary metathesis reaction followed first order kinetics.

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 β-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 β-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 β-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 β-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 %.

scholarly journals Fishing for the right catalyst for the cross-metathesis reaction of methyl oleate with 2-methyl-2-butene

2017 ◽  
Vol 7 (6) ◽  
pp. 1284-1296 ◽  
Author(s):  
A. Sytniczuk ◽  
A. Kajetanowicz ◽  
K. Grela
Keyword(s):  
Methyl Oleate ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
The Cross ◽  
The Right

A comparison of the reactivity of different ruthenium-based complexes in the cross-metathesis reaction of methyl oleate was presented.

Exploiting the cross-metathesis reaction in the synthesis of pseudo-oligosaccharides

2009 ◽  
Vol 7 (12) ◽  
pp. 2635 ◽  
Author(s):  
Paolo Ronchi ◽  
Stefano Vignando ◽  
Sara Guglieri ◽  
Laura Polito ◽  
Luigi Lay
Keyword(s):  
Metathesis Reaction ◽  
Cross Metathesis ◽  
The Cross

scholarly journals Relay cross metathesis reactions of vinylphosphonates

2014 ◽  
Vol 10 ◽  
pp. 1933-1941 ◽  
Author(s):  
Raj K Malla ◽  
Jeremy N Ridenour ◽  
Christopher D Spilling
Keyword(s):  
Reaction Mechanism ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Cross Metathesis ◽  
Metathesis Reactions ◽  
Terminal Alkenes ◽  
The Cross

Dimethyl (β-substituted) vinylphosphonates do not readily undergo cross metathesis reactions with Grubbs catalyst and terminal alkenes. However, the corresponding mono- or diallyl vinylphosphonate esters undergo facile cross metathesis reactions. The improved reactivity is attributed to a relay step in the cross metathesis reaction mechanism.

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