80434-60-2Relevant academic research and scientific papers
Multicatalytic Stereoselective Synthesis of Highly Substituted Alkenes by Sequential Isomerization/Cross-Coupling Reactions
Romano, Ciro,Mazet, Clément
, p. 4743 - 4750 (2018/04/10)
Starting from readily available alkenyl methyl ethers, the stereoselective preparation of highly substituted alkenes by two complementary multicatalytic sequential isomerization/cross-coupling sequences is described. Both elementary steps of these sequences are challenging processes when considered independently. A cationic iridium catalyst was identified for the stereoselective isomerization of allyl methyl ethers and was found to be compatible with a nickel catalyst for the subsequent cross-coupling of the in situ generated methyl vinyl ethers with various Grignard reagents. The method is compatible with sensitive functional groups and a multitude of olefinic substitution patterns to deliver products with high control of the newly generated C=C bond. A highly enantioselective variant of this [Ir/Ni] sequence has been established using a chiral iridium precatalyst. A complementary [Pd/Ni] catalytic sequence has been optimized for alkenyl methyl ethers with a remote C=C bond. The final alkenes were isolated with a lower level of stereocontrol. Upon proper choice of the Grignard reagent, we demonstrated that C(sp2) - C(sp2) and C(sp2) - C(sp3) bonds can be constructed with both systems delivering products that would be difficult to access by conventional methods.
METATHESIS POLYMERIZATION METHODS
-
Page/Page column 41-42, (2016/05/02)
The present disclosure is directed to methods of making a polymer, including exposing a reaction mixture including a strained cyclic unsaturated monomer and an organic initiator to a stimulus to provide an activated organic initiator, whereby the activate
Metal-free ring-opening metathesis polymerization
Ogawa, Kelli A.,Goetz, Adam E.,Boydston, Andrew J.
supporting information, p. 1400 - 1403 (2015/02/19)
We have developed a method to achieve ring-opening metathesis polymerization (ROMP) mediated by oxidation of organic initiators in the absence of any transition metals. Radical cations, generated via one-electron oxidation of vinyl ethers, were found to react with norbornene to give polymeric species with microstructures essentially identical to those traditionally obtained via metal-mediated ROMP. We found that vinyl ether oxidation could be accomplished under mild conditions using an organic photoredox mediator. This led to high yields of polymer and generally good correlation between Mn values and initial monomer to catalyst loadings. Moreover, temporal control over reinitiation of polymer growth was achieved during on/off cycles of light exposure. This method demonstrates the first metal-free method for controlled ROMP.
Stereoselectivity of the Thermally Initiated Free-Radical Chain Addition of Cyclohexane to 1-Alkynes
Metzger, Juergen O.,Blumenstein, Michael
, p. 2493 - 2500 (2007/10/02)
Alkanes can be added to alkynes in a thermally initiated free-radical chain reaction ("ane reaction").The addition of cyclohexane to 1-alkynes 1a-l yields a mixture of (Z)- and (E)-2-cyclohexyl-1-alkenes 3a-l.An essential step in this reaction is the addi
