Alkene

Synthesis of an Alkyne: Bromination of Stilbene and Dehydrohalogenation of Dibromide Maya Yagan Fall 2015 Lab Section 355-01 Lab Partner: Kristine Thao Abstract Trans-stilbene (1,2-diphenylethene) was synthesized in a two-step reaction. Trans-stilbene was brominated to give meso-stilbene dibromide in the first reaction. The stilbene dibromide was heated with base in order to induce dehydrobromination. One of the methods used throughout this experiment was vacuum filtration. An 81% yield

The purpose of this experiment was to perform a wittig reaction, the horner-emmons wittig specifically, reacting an aldehyde with an ylide to make an alkene. This particular variation of the wittig reaction has several advantages: It gives only the trans product; it uses a much milder base that is easier to handle; and it gives a water soluble byproduct which is easy to separate from the product. The reason that these advantages occur is a change in the structure of the ylide. Instead of a tripheylphosphine

was added into all the three test tubes. In the first test tube, 2 cyclohexanol was added. In the second test tube cyclohexene was added and for the third test tube 2 drops of product was added. The observations were recorded. Similarly, for the alkene test, 3 test tubes were labeled, and 20 drops of dichloromethane was added to each. Next, cyclohexanol was added to the first tube, cyclohexene in the second test tube and the product in the third test tube. Then, 5 drops of PBP which is the source

1-bromobutane and 2-bromobutane to form the alkene products 1-butene, trans-2-butene, and cis-2-butene. The dehydration reactions react under and acid-catalysis which follows an E1 mechanism. It was found that dehydration of 1-butanol yielded 3.84% cis-2-butene, 81.83% trans-2-butene, and 14.33% 1-butene, while 2-butanol is unknown due to mechanical issues with the GC machine. For the dehydrobromination, with the addition of a

Elimination Reactions of Alkyl Halides Purpose The purpose of this lab is to understand the process of eliminating an alkyl halide to form an alkene. The experiment is carried out by first converting the alcohol, 2-methy-2-butanol, into the alkyl halide of 2-chloro-2-methylbutane that will then be put through dehydrohalogenation that favors elimination reaction (E2) to create a mixture of 2-methyl-2-butene by alcoholic potassium hydroxide (KOH⁻) base and 2-methyl-1-butene by potassium tert-Butoxide

Keghan Chapter 8 MULTIPLE CHOICE QUESTIONS Topic: Structure Elucidation 1. An alkene adds hydrogen in the presence of a catalyst to give 3,4-dimethylhexane. Ozonolysis of the alkene followed by treatment with zinc and acetic acid gives a single organic product. The structure of the alkene is: CH3 A) CH3CH=C-CHCH2CH3 (cis or trans) CH3 CH3 B) CH3CH2C=CCH3 (cis or trans) CH2CH3 C) CH3 CH2=CCH2CHCH2CH3 CH3 CH2 D) CH3CH2CCHCH2CH3 CH3 CH3 E) CH3CH2CHCHCH=CH2

specific locations in aldehydes and ketones (Bernard & Ford, 1983). The overall reaction mechanism is shown in Figure 4. Figure 4. The Wittig Reaction - Formation of a transitional oxaphosphetane and resultant formation of a new carbon-carbon alkene bond resulting in the synthesis of 1,3-butadienes from aldehydes and ketones. Protocols for synthesising 1,3-butadienes from aldehydes and ketones have been established in the literature. The synthesis protocol identified by Greatrex et al. (2014)

Organic Chemistry-Diels Alders Reactions Introduction Diels-Alder reactions are organic chemical reactions which involve [2 + 4] cycloaddition. The cycloaddition takes place between the conjugated dienes and the substituted alkenes (dienophiles). This interaction between the dienophiles and conjugated dienes result in the formation of substituted cyclohexene system. In 1928, two scientists (Kurt Alder and Otto Diels) jointly invented Diels-Alder reaction. This invention enabled them to receive

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

student under Diels, were awarded the Nobel Prize in Chemistry for their work on the discovery of a reaction that is commonly practiced still to this day1. The reaction that is presently known as Diels-Alder reaction involves dienes reacting with alkenes to form cyclic compounds1. Diels-Alder reactions are among the most resourceful in organic synthesis due to the fact that they are relatively simple to carry out, produce a high amount of product, and the compounds produced are highly stereo-specific2