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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. This particular catalyst and set of reaction conditions led to the mostly regioselective and enantioselective 1,6-Michael addition of ethyl sorbate 1 to product 3 .
To this stirred mixture was added dropwise over 1 hour a solution of 1.79 g (12 mmol) of phosphorus oxychloride (freshly distilled from potassium carbonate), trichloroacetyl chloride (12 mmol), and 10 mL of anhydrous ether. The mixture was then stirred at reflux for 4 hours and the residual zinc removed by filtration on a pad of Celite.
[2] 1,2-disubstituted Cycloalkene undergoing syn and anti addition. Syn addition is the addition of two substituents to the same side (or face) of a double bond or triple bond, resulting in a decrease in bond order but an increase in number of substituents. [3] Generally the substrate will be an alkene or alkyne.
In this notation, a Diels-Alder reaction is a (4+2)cycloaddition and a 1,3-dipolar addition such as the first step in ozonolysis is a (3+2)cycloaddition. The IUPAC preferred notation however, with [i+j+...] takes electrons into account and not atoms. In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition.
[2] [3] [4] This type of reaction is also called a 1,2-nucleophilic addition. The stereochemistry of this type of nucleophilic attack is not an issue, when both alkyl substituents are dissimilar and there are not any other controlling issues such as chelation with a Lewis acid, the reaction product is a racemate. Addition reactions of this type ...
[1] [2] Hence, the reaction is sometimes referred to as the Huisgen cycloaddition (this term is often used to specifically describe the 1,3-dipolar cycloaddition between an organic azide and an alkyne to generate 1,2,3-triazole). 1,3-dipolar cycloaddition is an important route to the regio-and stereoselective synthesis of five-membered ...
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The 1 H two-dimensional NOE spectroscopy (NOESY) experiment and its extensions are important tools to identify stereochemistry of proteins and other biomolecules in solution, whereas in solid form crystal x-ray diffraction typically used to identify stereochemistry. [1] [2] [3] The heteronuclear NOE is particularly important in 13 C NMR ...