Dimmethyl Carvone Stereochemistry

5. Introduction
In this experiment, stereochemistry was explored by the isomerization of dimethyl maleate and the analysis of carvones. The isomerization was accomplished with the use of bromine, which broke the double bond to allow bond rotation. Free bond rotation allowed molecules to shift into the trans state before the double bond was reformed to create dimethyl fumarate. Weight and melting point of the crystals formed were taken for further analysis. Enantiomeric carvones were compared by odor and optical rotation for analysis. The data collected from the comparison was used to analyze the physical and chemical properties of enantiomers.
6. Data and Results Dimethyl maleate was converted to dimethyl fumarate through
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In chiral environments one enantiomer undergoes a chemical reaction more rapidly than the other. As such, the enantiomeric carvones smell different because they interact with the chiral active sites of receptors. The optical rotations of both carvones were measured by a polarimeter. A polarimeter passes light through a polarizer so that plane-polarized light then passes through the sample. Diastereomers are either achiral, meaning they do not have stereocenters, or they may have two or more stereocenters. Achiral molecules do not exhibit optical activity. Some diastereomers are meso, which describes a configurational isomer that has two stereocenters and is superimposable to its mirror image. Unlike enantiomers, diastereomers do not have identical chemical and physical properties.
Dimethyl maleate and dimethyl fumarate are a pair of diastereomers. At room temperature, dimethyl maleate is a liquid and dimethyl fumarate is a solid. They can be interconverted into each other by breaking the carbon-carbon double bond into a single bond and allowing the molecule to rotate before reforming the double bond. A bromine radical is formed by the breaking of a bromine-bromine bond in the presence of strong light. The double bond is broken by the bromine radical, which binds to one of the carbons. This allows of the free bond rotation of the molecule. Once the rotation has occurred, the bromine radical will dissociate from the molecule and the double bond will reform. At the end, two bromine radicals form a bromine-bromine

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