CHEM 239 Organic Chemistry - University of Washington. Quiz Section _ Chapter 22 Worksheet

CHEM 239 Organic Chemistry - University of Washington. Quiz Section _ Chapter 22 WorksheetChem 239 Chapter 22 Worksheet Work in groups of 3-4 to solve the following problems. Some of these questions are meant to be challenging and to encourage a productive discussion with your groupmates. This worksheet is substantially longer than 50 minutes and is designed to provide extra practice for you after the quiz section. Complete at least 2 questions to earn participation credit. Make sure all group members are indicated on Gradescope. 1) For each series of compounds, rank them in order of acidity and explain your reasoning. In theory, halogenation of an aldehyde/ketone could occur multiple times. a) Draw all possible bromination products for the following reaction. b) b) In practice, acidic halogenations tends to only halogenate once, while basic c) halogenations tend to halogenate multiple times. Why is this? Hint – What does the d) halogen do to any intermediates in the acidic or basic reaction? 3) As we will see in Chapter 24, sugars can exists in cyclic and linear forms. Below are the linear forms of glucose and fructose. Draw curved-arrow mechanisms for how glucose and fructose can interconvert under either acidic or basic conditions. 4) Keto/enol isomerization also occurs for nitrogen based compounds. Draw an “enol” type isomer of the following imine. Where did we see this intermediate previously? 5) None of the following compounds could do an aldol or Claisen condensation with a second molecule of themselves. Why not? 6) Ketones and esters could react with each other via enolates. a) Draw 4 condensation products that could be formed when the following ketone and ester are mixed with base. b) Suggest a way to selectively have the ketone enolate attack the ester to give that product. c) Suggest a way to selectively have the ester enolate attack the ketone to give that product. 7) Let’s walk through the Robinson annulation. a) First, a Michael addition occurs between an enolate and an unsaturated ketone. Draw the mechanism and product of this reaction. b) What aldehyde/ketone could be used to synthesize the enone in part A? c) Second, the product from part A undergoes an intramolecular aldol condensation and dehydration. Draw the mechanism of this reaction. d) On the final product, indicate which atoms came from acetophenone and which came from 4-methylpent-3-en-2-one. Also briefly explain why the product has the drawn cyclohexene ring structure, rather than a different ring that could have been formed from the intramolecular aldol condensation. e) Could the acetoacetic acid synthesis be used to make the acetophenone in part A? Why or why not? 8) Propose a synthesis of the following targets using either an aldol condensation, Claisen condensation, Robinson annulation, malonic acid synthesis, or acetoacetic acid synthesis. You should use each synthesis for exactly 1 of the targets. No other C-C forming reactions (e.g. Diels-Alder, Grignard, electrophilic aromatic substitution, etc.) should be used. Hint – each of these syntheses creates a product that looks very different from the original reactant so your first step should be to consider what sort of molecule each of the above reactions makes) 9) Mechanism practice! Draw curved arrow mechanisms for each reaction in question 8.