In-depth Organic Chemistry Exam 3 Assignment

General Information: The exam will have a layout identical to this study guide. Every question on the exam is presented here (with different structures etc.) but not all questions presented here will appear on the exam. For any ranking question, be sure to read the directions carefully, some questions differ in which direction you are to rank and these may be different between the study guide and your version of the exam. The additional information you will have on the exam will be the periodic table. Question specific information: Draw the products as indicated by the curvy arrows. Be sure to use correct charges. If 1) multiple resonance forms are possible, you MUST draw the one indicated by the curvy arrows. 2) Based on the products drawn, draw curvy arrows that will account for the given reaction. 3) Give the missing piece for each reaction. If the starting material is given as a name, you must give the structure in addition to the missing piece of the reaction. If more than one product is possible (i.e. major/minor products) only give the major product. Stereochemistry is very important. If your product should contain stereochemistry, be sure to include correct dash/wedge. If the product should NOT have stereochemistry (i.e. HBr addition) just draw a line without dash/wedge to indicate there is no stereochemistry implied. For example, because hydroboration/oxidation is a syn-addition process, you need to indicate that the H/OH are on the same face. However, if the product only creates one chiral center, no stereochemistry is needed because it doesn’t matter. These questions are concerned with relative stereochemistry not absolute stereochemistry; therefore, it doesn’t matter which face the initial attack occurs so long as the subsequent attack (if appropriate) occurs from the correct face. (i.e. the addition of Br2 can occur on either face but the second Br must be on the opposite side of where the first adds, so if the first is wedge, the second must be dash and vice-a-versa) 4) The mechanisms will be graded with great attention to detail. All arrows must start from the electrons (lone pairs or bonds) and go to the correct location. In addition, the arrow needs to have the correct number of “heads” (double headed for two electrons and single headed for one electron). • Possible mechanisms for the test o HX addition to an alkene (Ch. 6) o H2SO4/H2O or H2SO4/alcohol addition to an alkene (Ch. 6) o X2 addition to an alkene (Ch. 6) o X2/H2O addition to an alkene (Ch. 6) o SN1 reactions (Ch. 9) Questions 5 through the end: Each question refers to a pair of reactions given below and are labeled so you know which reaction pair to look at to answer the multiple-choice questions. Foe each, identify which reaction of the pair is faster or if they occur at the same rate. You will need to use the relative rate discussions in chapter 9 to answer these questions. 1) Noting the curvy arrows, draw all the product(s), organic and inorganic, of the following reactions. O + C N O + H O + H O S OH O 2) Draw curved arrows to show electron reorganization for the reaction step. O O Cl + O O OH Cl H O + Br Br S H3C S Br O + Br O H + H H O H + H2O 3) Fill in the best missing reagent(s), reactant(s), or product(s). Include stereochemistry and regiochemistry where appropriate. If more than one product is possible, draw only the major product. H2SO4 H2O Δ 1 equiv. Cl2 HBr I KCN H2SO4 H2O Δ I2 OH H2O Cl I KCN DMSO OsO4 tBuOOH HBr (E)-3-methyl-3-hexene 1. Hg(OAc)2, H2O 2. NaBH4 1. Br2 OH 2. Br Br2 HO H2O H2 Pd H2SO4 H2O, Δ 1. O3 2. SMe2 1. Hg(OAc)2, H2O 2. NaBH4 1-(sec-butyl)cyclohexene O Br ONa NaS Br OH 1. O3 2. SMe2 OsO4 tBuOOH EtOH Br 1. O3 2. SMe2 1. BH3 2. H2O2 NaOH OH Vinylcyclopentane 1. BH3 2. H2O2, NaOH 4) For the following reactions, draw complete “curvy arrow” mechanisms. Include all intermediates, charges, and stereochemistry. a. Indicate the slow step by writing “slow” by the reaction arrow of the slow step HBr Br b. Indicate the slow step by writing “slow” by the reaction arrow of the slow step H2SO4 O tBu Δ OH Would the reaction be faster, slower, or the same rate if the reaction were performed with 2,2,6-trimethyl-6-hept-6-en-3-ol (see below) and why? H2SO4 Δ OH 2,2,6-trimethylhept-6-en-3-ol O tBu c. Indicate the slow step by writing “slow” by the reaction arrow of the slow step Br HBr d. Provide mechanisms to arrive at each of the two products. If you use some of the same structures for each product, you only need arrive at that structure once. H2SO4 + H2O Δ OH OH e. O I2 OH I f. You only need to provide a mechanism for the first product (the ether) and not the alkene. The mechanism to form the alkene will be part of the next exam. Br CH3OH OCH3 + Ø Use the reactions below to answer multiple choice questions 5 to 8 5) Compare the rate of reaction for reactions C and D? a. Reaction C is faster b. Reaction D is faster c. Reactions C and D occur at the same rate 6) Compare the rate of reaction for reactions E and F? a. Reaction E is faster b. Reaction F is faster c. Reactions E and F occur at the same rate 7) Compare the rate of reaction for reactions G and H? a. Reaction G is faster b. Reaction H is faster c. Reactions G and H occur at the same rate 8) Compare the rate of reaction for reactions J and K? a. Reaction J is faster b. Reaction K is faster c. Reactions J and K occur at the same rate Ø Draw the correct major organic product for the following reactions Cl NaBr MeOH Cl Reaction C NaI MeOH Reaction D NaSMe NaSMe DMF DMF I Cl Reaction E Br Reaction F NaI H2O Reaction G Br Reaction J H2O Br Reaction H Br KOEt DMSO NaSEt DMSO Reaction K