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234-e4-SP08-key - CHEM 234 — Exam 4-— Spring 2008 Name...

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Unformatted text preview: CHEM 234 — Exam 4 -— Spring 2008 Name: H92; l. (32 points) Predict the product(s) for the following reactions. ' If more than one product is likely to be formed in significant quantity, indicate which is the major product. ' Where stereoisomers are possible, clearly Show all stereoisomersformed. A) 0504 NaHS03 §\\S “W 7173“" as /g/ : pyn me 2 g? 3.3% M’g’g W i f {:5 5% sw/ _M&M‘:rr~‘l"”’”‘mwfl ,,w “w“m‘ew 4- 4121 w ”I" f B) 18’» HO , 25% (l equivalent) 9‘0}. Bi (&Qi€3\" gang 4? 5 H2 / Pt , “it“ ———-———.._.____.> é, QAAUA‘ M f’?’;;/ "x hi f3 2 \7 ,,,,,, j mgwiav M’sg @W’ege C) 4M D) Hl { if: fimm ;WM:} 3: \ {egg as»: «in? i f, . \ \E ii i“ 5“ / ‘e/xf‘EMK‘. \wmwr“ 2. (16 points) Predict the MAJOR product for the following reactions. You do not need to show all stereoisomers. A) H O 2 . x / 0 fi H2804 (catalytic) , k C i o 9% accef‘vzé V B) / 1) BHgiTHF -----——-—-——-«> 2) H202, OH— 3. (10 points) Compound A (CngsBr) is a tertiary alkyl bromide. The compound is treated with sodium ethoxide in ethanol to give compound B (CgHM). Ozonolysis of B gives the compound below as the only product. Give the structures of A & B. o 2 Naive gm, (”$.53 2 .uIIlH" 5%¢W&M 43*? ® Qfiéé 4. (10 points) For the following reaction, provide a complete, detailed arrow-pushing mechanism to get from the reactant to the final product. (Sufficient NaNH; is present for the reaction.) 0‘ NaNH2 NH4Cl —--—-~————-——-——-> -—~————-----b~ mineral oil / Cl 110—160°C 9 was (6 points) How many equivalents of NaNHz are required to carry out the following reaction. (Give the precise number needed to go to completion, without excess.) Briefly explain. Bf , g i " '“ "” H3C-—-C§C-——CH3 \‘i’g Br 6. (12 points) Clearly indicate the final products of the following reaction including all stereoi’somers. Draw a complete arrow—pushing mechanism for the formation of one of the stereoisomer rOdléC . Clearly indicate stereochemistry and charges at each step. <<.ws§§w~«, g‘sfifiw’ggfi Pméfie ”6 5; E ‘ 7. (14 points) Using the indicated starting materials as your only source of carbon atoms, outline a synthesis for the following molecule (cis- isomer only). You may use any other required reagents. Starting Materials Final Product “Mwmwwtmmt ? 03 fl “WMWWWWWWMW ; M ”*9 % "fi‘gfiigs 3 waged air gr ew ”swag” BONUS: (8 points) Show a detailed, arrow-pushing mechanism for the full reaction in question #28. The mechanisms for both reaction steps must be correct to receive credit. (ztéféfilg’ g5} "57? a; ‘ Km :ggeem \n H (3* “19 Ngxk :’Q”O\fi i tag-we a pKa chart: . Values are approximate. ° «R = represents a generic alkyl group. ° A line off ofa carbon with no indicated substituent may be considered an alkyl group. Species pKa Hi -10 H2804 —9 HBr —9 HCl —7 ROH;+ —-2 ~ —4 Had -1.74 H3PO4 2 o A R OH NH4" 9.2 OH g 9.9 H20 15.7 CH3CHZOH 16 (CH3)3COH 18 ,______.____ R~CEC~H 25 _“ NH3 38 l. i— .4 /%/H ~ 44 t . . . ' ‘l—r" V 0'! 0 e... Various Reactions: ' Reaction conditions are not given for all reactions. Reaction conditions and/or substrates may be general and can vary. Some processes are reversible with varying conditions. Stereochemistry of reactions is NOT given except where indicated. 0 O —R = represents a generic alkyl group A, B, X, Y = represent various groups A line off of a carbon with no indicated substituent may be considered an alkyl group. Selected Hydrogenations: conditions only H2, Pd/CaCO3 HC=CR -—-———-—-—> syn addition quinoline Li, CH30H2NH2, -7e°c NH4CI Selected Alkene Oxidations: conditions only KMnO4 (cold) RZC==CR2 -——--———-———-> OH", H20 0504 NaH803 [220:0]?2 --—--—-> -—-—> pyridine H20 Alkene Cleavages: conditions only Hot potassium permanganate 1) KMnO4, OH ', heat 2) H30+ Ozonolysis 1) 03, CHZClz, ~78 c 2) Zn / HOAc anti addition Selected Hydrations: conditions only Oxymercuration - demercuration 1) Hg(OAc)2/ THF-HZO 2) NaBH4, OH“ Hydroboration - oxidation 1) 8H3:THF 2) H202, OH— ...
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