2 Cyclohexene Lab Report

The objective of this lab was to create a ketone through an oxidation reaction using a using a secondary alcohol and oxidizing agent in order to use that ketone in a reduction reaction with a specific reducing agent to determine the affect of that reducing agent on the diastereoselectivity of the product. In the first part of this experiment, 4-tert-butylcyclohexanol was reacted with NaOCl, an oxidizing agent, and acetic acid to form 4-tert-butylcyclohexanone. In the second part of this experiment, 4-tert-butylcyclohexanone was reacted with a reducing agent, either NaBH4 in EtOH or Al(OiPr)3 in iPrOH, to form the product 4-tert-butylcyclohexanol. 1H NMR spectroscopy was used to determine the cis:trans ratio of the OH relative to the tert-butyl group in the product formed from the reduction reaction with each reducing agent. Thin-layer chromatography was used in both the oxidation and reduction steps to ensure that each reaction ran to completion.

Two forms of stereochemistry can form product for the bromination of trans-cinnamic acid. Cis addition, also known as syn addition, is one way of forming product. This form of stereochemistry allows for the components of the reagent to add to the same side of the double bond. Trans, also known as anti addition, is the second form of addition that can create product for this experiment. Tran stereochemistry occurs when the components of the reagent add to opposite sides of the double bond. In this experiment, the formation of either erythro-2,3-dibromo-3-phenylpropanoic acid (trans/anti-R,S or S,R) or threo-2,3-dibromo-3-phenylpropanoic acid (cis/syn-R,R or S,S) was expected to occur.

We used TLC analysis to identify each product obtained from the dihydroxylation reactions by spotting a TLC plate with the product of our reaction, a solution of cis-cyclohexane, trans-cyclohexane, and a 50:50 mixture of the two. We then placed the plate in a beaker with ethyl acetate saturating the atmosphere to allow the TLC plate to develop. Finally, we compared Rf values of the components of the mobile phase, after the phase was completed. 100% ethyl acetate was used instead of 100% Hexane or a mixture of Ethyl Acetate, because ethyl acetate has high polarity and can separate the components of a mixture to elution, unlike hexane, which is non-polar, and therefore unable to separate the components of the mixture. A 50:50 mixture of both would not work, because the polar and non-polar compounds would neutralize the mixture, and thereby not separate the components of the mixture.

The purpose of this lab was to carry out a dehydration reaction of 2-methylcyclohexanol by heating it in the presence of phosphoric acid and determining which alkene product would be the major product. Methylcyclohexanols were dehydrated in an 85% phosphoric acid mixture to yield the minor and major alkene product by elimination reaction, specifically E1. The alkenes were distilled to separate the major and minor products and gas chromatography was used to analyze the results and accuracy of the experiment. The hypothesis was the major product of the reaction would be the most substituted product. This conclusion was made because of

The major reaction that happened was an E1 reaction (otherwise known as a unimolecular elimination reaction). In this reaction the removal of an HX substituent group results in the formation of a double bond via beta hydrogen elimination4. In an E1 reaction the deprotonation of hydrogen in the beta position occurs and from here a carbocation is formed, which results in the formation of an alkene product. This happens when the OH group on the 2-methylcyclohexanol is hydrated by H2SO4, which allows the OH to become an H2O. Since H20 is a better leaving group now it will

The objective of this lab was to allow a reaction to occur between the palladium onto the carbon and the cyclohexene. The reaction would allow the cyclohexene to undergo hydrogenation and produce benzene and cyclohexane. After this a gas-chromatography, which uses the compounds boiling points and polarity, was done to see the ratio and yield of the two products.

The carbon dioxide bubbles were observed during this reaction and used to determine when the carbonic acid was completely absent from the isolated product. The extracted product was a dark brown color and the heating chips were subsequently removed. The crude isoannyl product’s melting point was observed for characterization and to compare it to the melting point of the isolated isoannyl product. The crude isoamyl was placed into a distillation flask for distillation. This allowed for even high temperatures to be used and for the product to condense and be collected in the Hickman still

In order for reaction to occurs, the LUMO of a certain molecule has to react to a HOMO of the molecules since LUMO accepts electrons whereas HOMO donates electrons. In order for the reactions to be favourable to one another the energy difference between the LUMO of a molecule and the HOMO of another molecule has to be small this will then lead to a formation of a sigma bond between both molecules. This is based on whether the molecules are asymmetrical or symmetrical.

The purpose if this experiment is to prepare 5-cis- and 5-trans-3-(4-methylphenyl)-2-propenoic acid ethyl ester using formation of a stabilize ylide and p-tolualdehyde in a methanol solvent. The stabilize ylide is formed by a reaction of phosphonium salt, triphenylphosphonium bromide, and aqueous sodium hydroxide. The products made under reflux are separated using liquid-liquid extraction, and purified using rotary evaporator. The product was analyze using H-nuclear magnetic spectroscopy to determine the desired prepare 5-cis- and 5-trans-3-(4-methylphenyl)-2-propenoic acid ethyl ester formed with hexane by products. The percent yield was 72%.

Another isomer of 1,4-dimethylcyclohexane is the cis isomer. Cis and trans isomers are diastereoisomers. It is impossible for them to be readily interconverted by a simple rotational process as they are identical conformations of the same isomer. In cis isomer, one methyl group is equatorial while the other one is axial. Chair flipping simply provides

The functional group testing in table 4 indicates there was a positive test with the 2,4- DNPH and chromic acid test concluding that the unknown could be an aldehyde. This supports the previous conclusion that the unknown could be Hexanal. Compared with the identification of the unknown, which was cyclohexanone. The results of the identified unknown doesn’t match the information found in the functional group testing. What was supposed to happen was that the chromic acid should’ve tested negative but the results came out positive. A possible error could’ve been missed labeling of the test tubes.

Upon heating, 1,3,5-hexatriene will undergo an electrocyclic ring closure to give 1,3-cyclohexadiene (Scheme 2). 1.1. Stereospecificity of Electrocyclic Reactions Electrocyclic reactions are completely stereospecific. For example, ring closure of (2E,4Z,6E)-2,4,6-octatriene yields a single product with cis methyl groups on the ring. Ring opening of cis-3,4-dimethylcyclobutene forms a single conjugated diene with one Z alkene and one E alkene (Scheme 3).

This experiment was ran to stimulate real life application scenarios in which products were determined through various techniques learned from the past. Requiring analytical thinking and preparation, as a product was synthesized within the right time frame, with limited amount of starting material. The three compounds shown above are reacted with various reagents, to yield the best halide-containing product. These reactions are conducted to test the prediction that reaction 1 proceeded through a bimolecular nucleophillic substitution (SN2) and reactions 2 and 3, went through unimolecular nuclephillic substitution (Sn1), due to carbocation rearrangements forming 2 products each through a stepwise process. Conducting various tests through separation and purification methods can test the reactions and their hypothesized pathway, also Analyzing data through infrared spectroscopy (IR), proton nuclear magnetic resonance (1H NMR) and gas chromatography (GC) can give a final overall picture to the synthesized product, along with purity of the product and efficiency of the reactions.

During this experiment the crude product (mixture of ortho and para nitrophenols) was run through a column chromatography. The point of the column chromatography was to separate the nitrophenols and purify them. During the experiment the crude product was ran through the silica with two different solvents. 60:40 DCM/hexanes was used to form the first band while 50:50 DCM/EtOAc was used to form the second band. The reason for this method was that there had to be a change in solvent for the para product because since it is polar it was expected to run very slowly through the column and therefore needed a more polar solvent to speed it up, ethyl acetate. As expected two different yellow bands were observed. Each band represented one of the nitrophenols, with the bottom band being the ortho-nitrophenol since it is less polar and stayed within the solvent and therefore ran through the column quickly. The para product stayed at the top because it was similarly polar to the Silica and had the ability to hydrogen bond to it. Once the bands were formed fractions were taken from the yellow bands. Fraction 1-5 was from the ortho product and fractions 6-10 were from the para product. The fractions formed were than ran through TLC chromatography to test the true purity of the products and the success of the column chromatography separation. The first TLC plate containing fractions 1-5, surprisingly did not have any spots (Figure 1b). This is was unexpected because fractions 1-5 were

Isoprene, 2-methyl-1,3-butadiene,is a volatile and colorless 5-carbon containing hydrocarbon and has boiling point at 34°C (Fig. 1.1). This is widely used as a building block for the many members of the isoprenoid family and moreover this family also includes the largest family of natural products with a variety of applications such as in production of chemicals and pharmaceuticals (Marienhagen & Bott 2013) (Hong et al. 2012)