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Sodium bis(2-methoxyethoxy)aluminium hydride (SMEAH; [1] trade names Red-Al, Synhydrid, Vitride) is a hydride reductant with the formula NaAlH 2 (OCH 2 CH 2 OCH 3) 2. The trade name Red-Al refers to its being a reducing aluminium compound. It is used predominantly as a reducing agent in organic synthesis.
In chemistry, a reagent (/ r i ˈ eɪ dʒ ən t / ree-AY-jənt) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. [1] The terms reactant and reagent are often used interchangeably, but reactant specifies a substance consumed in the course of a chemical reaction. [ 1 ]
An example is potassium dichromate, which does not pass the dangerous goods test of an oxidizing agent. The U.S. Department of Transportation defines oxidizing agents specifically. There are two definitions for oxidizing agents governed under DOT regulations. These two are Class 5; Division 5.1(a)1 and Class 5; Division 5.1(a)2. Division 5.1 ...
The template effects emphasizes the pre-organization provided by the coordination sphere, although the coordination modifies the electronic properties (acidity, electrophilicity, etc.) of ligands. [1] An early example is the dialkylation of a nickel dithiolate: [2] The corresponding alkylation in the absence of a metal ion would yield polymers.
In the S N 2 mechanisms, the nucleophile forms a transition state with the attacked molecule, and only then the leaving group is cleaved. These two mechanisms differ in the stereochemistry of the products. S N 1 leads to the non-stereospecific addition and does not result in a chiral center, but rather in a set of geometric isomers (cis/trans).
When a lithium enolate is generated in diethyl ether or methyl t-butyl ether, treatment with Mander's reagent will selectively afford the C-acylation product. [1] Thus, for enolate acylation reactions in which C- vs. O-selectivity is a concern, methyl cyanoformate is often used in place of more common acylation reagent like methyl chloroformate .
For example, the image below shows the addition of ethylmagnesium bromide to ethyl sorbate 1 using a copper catalyst with a reversed josiphos (R,S)-(–)-3 ligand. [35] This reaction produced the 1,6-addition product 2 in 0% yield, the 1,6-addition product 3 in approximately 99% yield, and the 1,4-addition product 4 in less than 2% yield.
Organic azides also provide an example of an insertion reaction in organic synthesis and, like the above examples, the transformations proceed with loss of nitrogen gas. When tosyl azide reacts with norbornadiene , a ring expansion reaction takes place in which a nitrogen atom is inserted into a carbon-carbon bond α- to the bridge head: [ 14 ]