Stereochemistry of Dihydroxylation Reactions
Stereochemistry of Dihydroxylation Reactions
Question: Can the stereochemical outcome of dihydroxylation reactions be determined by thin layer chromatography?
Overview: In this experiment, you will perform two reactions that transform alkenes into diols. While similar in functional group transformation, these reactions may lead to stereochemically different products. The two possible products are diastereomers of one another, and therefore have different physical chracteristics. After performing the reactions, you will characterize the crude reaction mixtures to determine if you formed a mix of trans enantiomers, the cis product, or a mixture of cis and trans diols. (Figure 1)
In this experiment, you will use a common oxidizing agent, KMnO4. You will also use an oxidizer that you may not have discussed in lecture called Oxone ®. Oxone is a persulfate mix that reacts with acetone to produce dimethyldioxirane.
Procedure: Oxone reaction
Dissolve 0.40 g oxone ® in 2.0 mL of water by shaking vigorously in a sealed vial. (Caution! Be sure the vial is sealed because oxone is a strong oxidizer.) Dissolve 50 L of cyclohexene in 2.0 mL of acetone in a small Erlenmeyer flask. Cool the cyclohexene solution in an icebath, then add the oxone solution dropwise over 5 minutes with swirling in the icebath. Remove the Erlenmeyer flask from the icebath and allow the reaction to sit for 15-30 minutes. (To save time, this is a good place to start the potassium permanganate reaction.) Add two drops of conc. HCl to the reaction with swirling. Allow the reaction to sit for about 10 minutes, swirling occasionally.
Procedure: Potassium permanganate reaction
Dissolve 100 mg of KMnO4 in 4.0 mL of 0.1 M NaOH solution in a small Erlenmeyer flask. Cool the KMnO4 solution in an icebath. Dissolve 50 L of cyclohexene in 2.0 mL of t-butanol in a separate container. Quickly add the cyclohexene solution into the potassium permanganate. Swirl the
Question: Can the stereochemical outcome of dihydroxylation reactions be determined by thin layer chromatography?
Overview: In this experiment, you will perform two reactions that transform alkenes into diols. While similar in functional group transformation, these reactions may lead to stereochemically different products. The two possible products are diastereomers of one another, and therefore have different physical chracteristics. After performing the reactions, you will characterize the crude reaction mixtures to determine if you formed a mix of trans enantiomers, the cis product, or a mixture of cis and trans diols. (Figure 1)
In this experiment, you will use a common oxidizing agent, KMnO4. You will also use an oxidizer that you may not have discussed in lecture called Oxone ®. Oxone is a persulfate mix that reacts with acetone to produce dimethyldioxirane.
Procedure: Oxone reaction
Dissolve 0.40 g oxone ® in 2.0 mL of water by shaking vigorously in a sealed vial. (Caution! Be sure the vial is sealed because oxone is a strong oxidizer.) Dissolve 50 L of cyclohexene in 2.0 mL of acetone in a small Erlenmeyer flask. Cool the cyclohexene solution in an icebath, then add the oxone solution dropwise over 5 minutes with swirling in the icebath. Remove the Erlenmeyer flask from the icebath and allow the reaction to sit for 15-30 minutes. (To save time, this is a good place to start the potassium permanganate reaction.) Add two drops of conc. HCl to the reaction with swirling. Allow the reaction to sit for about 10 minutes, swirling occasionally.
Procedure: Potassium permanganate reaction
Dissolve 100 mg of KMnO4 in 4.0 mL of 0.1 M NaOH solution in a small Erlenmeyer flask. Cool the KMnO4 solution in an icebath. Dissolve 50 L of cyclohexene in 2.0 mL of t-butanol in a separate container. Quickly add the cyclohexene solution into the potassium permanganate. Swirl the