Reductive Coupling Mechanism
Reductive Coupling Mechanism - Related Videos
01:27
Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
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2023
Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols. The radical reaction is initiated by a single electron transfer from metals like sodium and magnesium to a spin-paired molecule like aldehydes or ketones to generate a ketyl—a radical anion. The ketyl has a radical character on the carbon atom and a charge on the...
01:22
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
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2023
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction. The reaction is a two-step process. The mechanism is still under study, but for some reagent...
01:18
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
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2023
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
01:30
Transducer Mechanism: G Protein–Coupled Receptors
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2023
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs. GPCRs are also called heptahelical, 7TM, or...
06:19
Palladium-Catalyzed Cross Coupling
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2023
Source: Vy M. Dong and Faben Cruz, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the concept of a palladium-catalyzed cross coupling. The set-up of a typical Pd-catalyzed cross coupling reaction will be illustrated. Pd-catalyzed cross coupling reactions have had a profound effect on how synthetic chemists create molecules. These reactions have enabled chemists to construct bonds in new and more efficient ways. Such reactions have found widespread...
FAQs
Catalyst coordination brings the two substrates into a reactive arrangement, while electron transfer changes the metal and substrate electronic states. These changes help activate both partners for bond formation. After the new bond forms, the coupled product is released from a lower-valent metal center, linking catalyst redox changes directly to product formation and catalyst turnover.
Changes in metal oxidation state reflect the movement of electrons through the catalytic cycle and influence how substrates bind and react. A lower-valent metal center appears after bond formation and is associated with release of the coupled product. Tracking these changes helps chemists interpret catalyst behavior and understand why particular reaction pathways produce the desired connectivity.
A key distinction is the type of reaction partner required. Conventional cross-coupling generally uses a preformed organometallic partner, whereas reductive coupling may join two substrates without preparing one of them in that form beforehand. This difference can broaden the choice of starting materials and makes the method relevant to routes that seek simpler access to new carbon-carbon connections.
The sequence begins when a catalyst coordinates with and activates two substrates. Electron transfer then supports their productive interaction, followed by formation of a bond between the molecular fragments. The resulting coupled product separates from a lower-valent metal center. This sequence provides a framework for analyzing how substrate activation, bond formation, and product release are connected.
Chemists may select this strategy when they need to connect carbon-based fragments from readily available starting materials or avoid relying on a preformed organometallic partner. It is especially relevant to assembling complex molecules and designing shorter or more efficient synthetic routes. The approach therefore supports both practical bond construction and investigation of alternative catalyst-controlled reaction pathways.
Examining the mechanism can clarify how a catalyst coordinates substrates, transfers electrons, controls selectivity, and releases product. Those insights help researchers evaluate why a reaction favors a particular coupled structure and how catalyst behavior shapes the overall route. In chemistry, this knowledge also supports development of more efficient and potentially more sustainable bond-forming methods.