Cross Metathesis
Cross Metathesis - Related Videos
00:53
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
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2023
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process. Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
01:16
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
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2023
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
01:13
Olefin Metathesis Polymerization: Overview
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2023
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization. Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
08:45
Genetic Crosses
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2023
To dissect genetic processes or create organisms with novel suites of traits, scientists can perform genetic crosses, or the purposeful mating of two organisms. The recombination of parental genetic material in the offspring allows researchers to deduce the functions, interactions, and locations of genes. This video will examine how genetic crosses were influential in developing Mendel's three laws of inheritance, which form the basis of our understanding of genetics. One genetic crossing...
08:55
Making a Geologic Cross Section
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2023
Source: Laboratory of Alan Lester - University of Colorado Boulder Geologic maps were first made and utilized in Europe, in the mid-to-late 18th century. Ever since, they have been an important part of geological investigations all around the world that strive to understand rock distributions on the surface of the earth, in the subsurface, and their modification through time. A modern geologic map is a data-rich representation of rocks and rock-structures in a two-dimensional plan view. The...
FAQs
During the catalytic cycle, the two alkene partners interact with a metal-carbene center through alternating [2+2] cycloaddition and cycloreversion events. These steps pass through metallacyclobutane intermediates, temporarily organizing the reacting carbon frameworks before new alkylidene combinations emerge. The sequence matters because it determines which carbon-carbon double-bond products become accessible.
Ruthenium and molybdenum complexes can both serve as metal-carbene catalysts, but catalyst choice influences reaction activity, selectivity, and product distribution. Thus, the catalyst is not merely a reaction promoter: it helps determine how efficiently the alkene partners react and which substituted alkene products are favored. Matching catalyst choice to the substrate pair is therefore central to reaction design.
Because the reaction joins two different alkene partners, their structures help shape the resulting substituted alkenes and the distribution of products. Substrate selection must therefore be considered together with catalyst selection rather than treated as an independent choice. This pairing is especially important when a synthesis requires a particular carbon-carbon double-bond arrangement or a controlled product outcome.
Comparatively mild conditions and tolerance of many functional groups allow Cross metathesis to be considered when a target molecule contains chemically varied functionality. These characteristics support flexible molecular construction while the alkene-exchange process creates substituted alkene intermediates. As a result, researchers can apply the method to synthesis plans that benefit from broad substrate compatibility and access to valuable intermediates.
A basic planning workflow starts by identifying the two alkenes whose alkylidene fragments should be exchanged, then choosing a compatible metal-carbene catalyst, such as a ruthenium or molybdenum complex. Expected activity, selectivity, and product distribution should guide these choices. The resulting reaction is then considered in terms of the substituted alkene products it can provide for the larger synthesis.
Researchers may choose Cross metathesis when they need an efficient way to construct substituted alkenes from two alkene-containing components under comparatively mild conditions. Its functional-group tolerance broadens the molecular frameworks that can be considered. In pharmaceutical, polymer, and natural-product chemistry, the method can simplify molecular construction and provide access to valuable intermediates.