Synthesis of Symmetrical Trisubstituted Olefins by Cross Metathesis

2002 ◽  
Vol 4 (11) ◽  
pp. 1939-1942 ◽  
Author(s):  
Arnab K. Chatterjee ◽  
Daniel P. Sanders ◽  
Robert H. Grubbs
Keyword(s):  
Cross Metathesis ◽  
Trisubstituted Olefins

An Atom-Economic and Stereospecific Access to Trisubstituted Olefins through Enyne Cross Metathesis Followed by 1,4-Hydrogenation

Synlett ◽  
2018 ◽  
Vol 29 (06) ◽  
pp. 785-792 ◽  
Author(s):  
Hans-Günther Schmalz ◽  
Friederike Ratsch
Keyword(s):  
Functional Group ◽  
Cross Metathesis ◽  
Broad Scope ◽  
Trisubstituted Olefins

The combination of intermolecular enyne cross metathesis and subsequent 1,4-hydrogenation opens a stereocontrolled and atom-economic access to trisubstituted olefins. By investigating different combinations of functionalized alkyne and alkene substrates, we found that the outcome (yield, E/Z ratio) of the Grubbs II-catalyzed enyne cross-metathesis step depends on the substrate’s structure, the amount of the alkene (used in excess), and the (optional) presence of ethylene. In any case, the 1,4-hydrogenation, catalyzed by 1,2-di­methoxybenzene-Cr(CO)3, proceeds stereospecifically to yield exclusively the E-products from both the E- and Z-1,3-diene intermediates obtained by metathesis. A rather broad scope and functional group compatibility of the method is demonstrated by means of 15 examples.

scholarly journals A Relay Strategy Actuates Pre-Existing Trisubstituted Olefins in Monoterpenoids to Form New Trisubstituted Olefins by Cross Metathesis

2019 ◽  
Author(s):  
Karim Bahou ◽  
D. Christopher Braddock ◽  
Adam G. Meyer ◽  
G. Paul Savage ◽  
Zhensheng Shi ◽  
...  
Keyword(s):  
Geometrical Isomer ◽  
Successful Implementation ◽  
Enantiomerically Pure ◽  
Cross Metathesis ◽  
Trisubstituted Olefins ◽  
The Cross ◽  
Trisubstituted Alkenes

<b><u>Abstract:</u></b> A retrosynthetic disconnection-reconnection analysis of epoxypolyenes – substrates that can undergo cyclization to podocarpane-type tricycles – reveals relay-actuated Δ<sup>6,7</sup>-functionalized monoterpenoid alcohols for ruthenium benzylidene catalyzed olefin cross metathesis with homoprenyl benzenes. Successful implementation of this approach provided several epoxypolyenes as expected (<i>E</i>:<i>Z</i>, ca. 2-3:1). The method is further generalized for the cross metathesis of pre-existing trisubstituted olefins in other relay-actuated Δ<sup>6,7</sup>-functionalized monoterpenoid alcohols with various other trisubstituted alkenes to form new trisubstituted olefins. Epoxypolyene cyclization of an enantiomerically pure, but geometrically impure, epoxypolyene substrate provides an enantiomerically pure, trans-fused, podocarpane-type tricycle (from the <i>E</i>-geometrical isomer).<br>

scholarly journals A Relay Strategy Actuates Pre-Existing Trisubstituted Olefins in Monoterpenoids for Cross-Metathesis with Trisubstituted Alkenes

2020 ◽  
Vol 85 (7) ◽  
pp. 4906-4917 ◽  
Author(s):  
Karim A. Bahou ◽  
D. Christopher Braddock ◽  
Adam G. Meyer ◽  
G. Paul Savage ◽  
Zhensheng Shi ◽  
...  
Keyword(s):  
Cross Metathesis ◽  
Trisubstituted Olefins ◽  
Trisubstituted Alkenes

A Relay Strategy Actuates Pre-Existing Trisubstituted Olefins in Monoterpenoids to Form New Trisubstituted Olefins by Cross Metathesis

2019 ◽  
Author(s):  
Karim Bahou ◽  
D. Christopher Braddock ◽  
Adam G. Meyer ◽  
G. Paul Savage ◽  
Zhensheng Shi ◽  
...  
Keyword(s):  
Geometrical Isomer ◽  
Successful Implementation ◽  
Enantiomerically Pure ◽  
Cross Metathesis ◽  
Trisubstituted Olefins ◽  
The Cross ◽  
Trisubstituted Alkenes

<b><u>Abstract:</u></b> A retrosynthetic disconnection-reconnection analysis of epoxypolyenes – substrates that can undergo cyclization to podocarpane-type tricycles – reveals relay-actuated Δ<sup>6,7</sup>-functionalized monoterpenoid alcohols for ruthenium benzylidene catalyzed olefin cross metathesis with homoprenyl benzenes. Successful implementation of this approach provided several epoxypolyenes as expected (<i>E</i>:<i>Z</i>, ca. 2-3:1). The method is further generalized for the cross metathesis of pre-existing trisubstituted olefins in other relay-actuated Δ<sup>6,7</sup>-functionalized monoterpenoid alcohols with various other trisubstituted alkenes to form new trisubstituted olefins. Epoxypolyene cyclization of an enantiomerically pure, but geometrically impure, epoxypolyene substrate provides an enantiomerically pure, trans-fused, podocarpane-type tricycle (from the <i>E</i>-geometrical isomer).<br>

ChemInform Abstract: Synthesis of Symmetrical Trisubstituted Olefins by Cross Metathesis.

ChemInform ◽  
2010 ◽  
Vol 33 (42) ◽  
pp. no-no
Author(s):  
Arnab K. Chatterjee ◽  
Daniel P. Sanders ◽  
Robert H. Grubbs
Keyword(s):  
Cross Metathesis ◽  
Trisubstituted Olefins

scholarly journals Relay Cross Metathesis for the Iterative Ascent of the Terpenoids

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

<div>We report the design and implementation of a relay cross</div><div>metathesis (ReXM) reaction for the ascent of the terpenoids in an iterative protocol. The method features the reaction of naturally occurring terpenoid building blocks – with preexisting trisubstituted olefins – which combine to construct a new trisubstituted olefin resulting in a five-carbon unit homologation. Subsequent functional group manipulation allows for the method to be repeated in an</div><div>iterative fashion. The method is used for the synthesis of a diterpenebenzoate macrolide of biogenetic relevance to the bromophycolide family of natural products.</div>

Endgroup and Sidechain Functionalization of Surface-Initiated ROMP Thin Films: Progress Towards ROMP-Based Molecular Wires

2018 ◽  
Author(s):  
Nicholas Marshall
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Cyclic Voltammetry ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Ring Opening ◽  
Molecular Wires ◽  
Metathesis Polymerization ◽  
Cross Metathesis ◽  
Active Ester

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>

Synthesis of Conjugated Triynes via Alkyne Metathesis

2019 ◽  
Author(s):  
Idriss Curbet ◽  
Sophie Colombel-Rouen ◽  
Romane Manguin ◽  
Anthony Clermont ◽  
Alexandre Quelhas ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
High Selectivity ◽  
Alkyne Metathesis ◽  
Cross Metathesis ◽  
Synthetic Strategy ◽  
Sterically Hindered ◽  
Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

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