Chemistry can be defined as the study of matter and the changes it undergoes. You¡¯ll sometimes hear it called the central science because it is the connection between physics and all the other sciences, starting with biology. 16606-55-6, Name is (R)-4-Methyl-1,3-dioxolan-2-one, molecular formula is , belongs to copper-catalyst compound. In a document, author is Liu, Zheyuan, Product Details of 16606-55-6.
Mechanistic Studies of Copper(I)-Catalyzed Stereoselective [2,3]-Sigmatropic Rearrangements of Diazoesters with Allylic Iodides/Sulfides
Density functional theory calculations have revealed the mechanism and origin of regio- and stereoselectivity in [2,3]-sigmatropic rearrangements of diazoesters with allylic iodides/sulfides via chiral bisoxazoline-Cu(I) catalysts. Initially, the two catalytic systems share a similar process involving the generation of Cu(I)-carbene and the ensuing nucleophilic attack by allylic iodide/sulfide. Then, the rearrangements bifurcate at the generated metal-bound ylide species. For the iodonium ylide system, it prefers to undergo a Cu(I)-assisted five-membered envelope transition state to give the [2,3]-rearrangement product. However, for the sulfonium ylide system, it favors to form a free ylide that further allows a five-membered electrophilic transition state to offer the [2,3]-rearrangement product. The metal-bound ylide mechanism is disfavored for this [2,3]-rearrangement of sulfur ylide due to the severe substrate-ligand steric repulsions during the isomerization. Meanwhile, the free sulfonium ylide can be regarded as a sulfonium ylene with a C=S bond owing to the strong electronegativity of sulfur and is stable, which promotes this pathway. In contrast, the free iodonium ylide is more like a zwitterion with a carbanion and an iodine cation due to the low electronegativity of iodine and is unstable, which requires the copper(I) center to stabilize the rearrangement. The regioselectivity is derived from the electronic effect of phenyl on the charge distribution over the allyl moiety. The stereoselectivity is mainly controlled by substrate-ligand steric interactions, wherein the favored pathway tolerates less steric hindrance between the substitutes of carbene and allyl moieties and the bulky groups on bisoxazoline ligand.
Sometimes chemists are able to propose two or more mechanisms that are consistent with the available data. If a proposed mechanism predicts the wrong experimental rate law, however, the mechanism must be incorrect.Welcome to check out more blogs about 16606-55-6, in my other articles. Product Details of 16606-55-6.
Reference:
Copper catalysis in organic synthesis – NCBI,
,Special Issue “Fundamentals and Applications of Copper-Based Catalysts”