ORGANIC CHEMISTRY II (2302) 8:00 8:50 am, July 21, Exam 3

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1 NAME ID # ORGANIC CHEMISTRY II (202) 8:00 8:50 am, July 21, 2016 Exam If you want to pick this exam up Monday in class (in public), please check the box on the right: If you do not check the box, I will not bring your exam to class on Monday, and you will need to pick up your exam in private from Chemistry department staff in 115 Smith beginning Tuesday, July 26 th. Exams that are not picked up within two weeks will be disposed of. A periodic table and a chart of reaction conditions are attached to the back of this exam as aids. Otherwise, you are not permitted to use any other materials (including notes, books, or electronic devices of any kind). Right now, write your name and student ID number at the top of this page. When the exam begins, please write your name at the top of the next page. You may use pen or pencil. However, re-grades will be considered only for exams completed in pen. Please write your answers in the boxes/spaces provided. If your answer is not in the appropriate space (say, for example, it s on the back of the page), draw us an arrow and/or note telling us where to look. 1

2 NAME Scoring: 1. / / / / 2. / / 12 Total Score: / (12 pts) Each of the four carbonyl-containing compounds below is acidic, and would be deprotonated by a strong base like amide anion (NH 2 - ). Rank each molecule 1 through 4 in terms of its acidity, from most acidic (1) to least acidic (4). Then, for the two acids in the middle, draw the preferred conjugate base structure that would be generated by deprotonation with sodium amide (NaNH 2 ). rank each acid 1-4: NaNH 2 deprotonates these to: conjugate base: conjugate base: 2. (12 pts) Each of the reactions on the next page is drawn with two possible reaction conditions. If only one of the two reaction conditions would generate the given molecule as the major product, circle those conditions. If both sets of conditions would accomplish the reaction, circle. If neither set of reaction conditions would succeed, circle. Circle one answer only. 2

3 LDA NaN (1 equiv) 2. PPh, H 2 O 2. H 2 NNH 2 Br 2 Br 2 H O +. (20 pts) Each of the reactions on the next page is drawn with two possible products. If one of the two products predominates, circle that preferred product. If the two products are produced equally, circle. If neither product would result from the reaction, circle. Circle one answer only.

4 1. CH I (excess) 2. Ag 2 O, H 2 O + Pd(OAc) 2 PPh, NEt 1. LDA, -78 C, THF 2. NaBH CN 4

5 4. (21 pts) For the reaction shown below, draw a mechanism that explains how the product is generated from the starting material. In your answer, make sure that you: Draw each step of the mechanism separately; Use electron pushing to show where the electrons in each step go; Use only the molecules that you are given; do not invoke reactants or solvents that aren t in the problem. NaOCH CH OH Mechanism: 5

6 5. (2 pts) For each of the reactions on the following pages, fill in the empty box corresponding to reactants, reagents, or products. Give only one answer in each box. For reactions that you expect to yield multiple products, draw one major product. For reactions that yield multiple enantiomers, draw only one enantiomer in the box, and include the note + enantiomer. 1. (excess) NH 2. Na 2 CO { + H 2 C=CH 2 (gas) } 1. SOCl 2, pyridine O O N Li 5. LiOH 6. H O +. LDA an acyclic starting material 6

7 1. NaOCH 2 CH HOCH 2 CH 2. H O + + carbonyl-containing starting material used in excess? YES or NO? carbonyl-containing starting material used in excess? YES or NO? (circle one) 6. (12 pts) Propose a multistep synthesis of the product below, beginning with the starting materials given. In addition to those organic starting materials, you can use any reagents and reactions we ve learned about in class. You might discover multiple answers to this problem; draw only your best (one) synthetic route. Feel free to draw an incomplete route we will give you partial credit where we can. and multistep synthesis 7

8 Exam Chart of Reaction Conditions Br 2 FeBr Cl 2 AlCl H 2 SO 4 HNO Sn or Fe HCl/H 2 O H 2 SO 4 SO KMnO 4 - OH, 100 C Mg Et 2 O 1. NaNO 2 HCl 2. CuCN or H PO 2 or CuX or H O + 1. HO O Na 2 Cr 2 O 7 H 2 SO 4 HCl O 2. base. R-X 4. LiOH Bu 4 N + F - N OH Li R-X (R = alkyl) AlCl or FeBr 1. N 2 H 4 2. KOH, LiAlH(OtBu) PhCH 2 Br Ag 2 O NaNH 2 (LDA) CHCl KOtBu CH 2 I 2 Zn(Cu) 1. O 2. H 2 O 1. Ag 2 O NH 2. H O + 1. LiAlH 4 2. H 2 O SOCl 2 (& pyridine, usually) Pd(OAc) 2 PPh, NEt Pd(PPh ) 4 1. Zn(Hg), HCl/H 2 O RMgX 1. NaBH 4 2. H 2 O Li hexane 1. PPh 2. n-buli. O R (COCl) 2 RLi R' 1. CH I (excess) 2. Ag 2 O H 2 O. H 2 Pd-C R 2 CuLi Al H H Al R (DIBAL-H) O AlCl Cl (CH ) SiCl {TMSCl}, or TBDMSCl; Et N or imidazole N C N (DCC) RCHO Na(OAc) BH or NaBH CN 2. N 2 H 4 (or - OH) (Grubbs catalyst)

9 Gold Periodic Table of the Elements Chemistry Reference Sheet California Standards Test A H 1 Hydrogen 1.01 Li Lithium 6.94 Na 11 Sodium K Potassium Rb Rubidium A 104 Rf Rutherfordium (261) 42 Mo Molybdenum Atomic number Na Element symbol Sodium Element name Average atomic mass* Cs 55 Cesium Fr Francium (22) Be 4 Beryllium 9.01 Mg 12 Magnesium Ca Calcium Sr Strontium Ba 56 Barium Ra Radium (226) B 21 Sc Scandium Y Yttrium La 57 Lanthanum Ac Actinium (227) 4 4B 22 Ti Titanium Zr Zirconium Hf Hafnium B 2 V Vanadium Nb Niobium Ta 7 Tantalum Db Dubnium (262) 6 6B 24 Cr Chromium B 4 Tc Technetium (98) W 74 Re 75 Rhenium Tungsten Sg Seaborgium (266) 25 Mn Manganese Bh Bohrium (264) Key 8 26 Fe Iron Ru Ruthenium Os 76 Osmium Hs Hassium (269) 9 8B 27 Co Cobalt Rh Rhodium Ir Iridium Mt Meitnerium (268) Ni Nickel Pd Palladium Pt Platinum B 29 Cu Copper Ag Silver Au B 0 Zn Zinc Cd Cadmium Hg 80 Mercury A Boron A B 5 Carbon Al Aluminum Ga Gallium In Indium Tl Thallium Ge Germanium A C 6 Nitrogen Si Silicon Sn Tin Pb 82 Lead A N 7 Oxygen P Phosphorus 0.97 As Arsenic Sb Antimony Bi Bismuth A O 8 Fluorine S Sulfur Se Selenium Te Tellurium Po 84 Polonium (209) 18 8A He 2 Helium F 9 Ne Neon Cl Chlorine Br Bromine I Iodine At Astatine (210) 18 Ar Argon Kr Krypton Xe Xenon Rn 86 Radon (222) * If this number is in parentheses, then it refers to the atomic mass of the most stable isotope. Ce 58 Cerium Th 90 Thorium Pr Praseodymium Pa 91 Protactinium Nd 60 Neodymium U Uranium 28.0 Pm 61 Promethium (145) Np 9 Neptunium (27) Sm 62 Samarium Pu 94 Plutonium (244) Eu 6 Europium Am 95 Americium (24) Gd 64 Gadolinium Cm 96 Curium (247) Tb 65 Terbium Bk 97 Berkelium (247) Dy 66 Dysprosium Cf Californium (251) Ho 67 Holmium Es 99 Einsteinium (252) 68 Er Erbium Fm 100 Fermium (257) Tm 69 Thulium Md Mendelevium (258) Yb 70 Ytterbium No Nobelium (259) Lu 71 Lutetium Lr Lawrencium (262) Copyright 2008 California Department of Education