3_19_2001 key

3_19_2001 key - NAME CHEMISTRY 130B (B.H. Lipshutz) Final...

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Unformatted text preview: NAME CHEMISTRY 130B (B.H. Lipshutz) Final Exam March 19, 2001 i a 15 32 19 15 15 5+1O 15 3x6 18 extra credit 20 15 . 9+16+7 . 4+4+6+5 KEY M8 (a o 0 qk if; D I I!“ H "'11, @) gnu @) /\'/\I/\ 00th (d) 001/6? (6 (fl E:§;au H101, Ha“ I. 2. 3. HSMSH. thFs +. Ra. Ni, Hz .. Lem, 2m 2- P061 OHin 3. Ha. NNHPhx‘ z, wt:er 3. Ndsuil'tm" Hao" rt l- PBrs. cuzua. 2. H2 I 003 cy/moh’nc 3. Hz-N—F, M. H"' 600M ;4/ H 601/ W 1. Predict the major organic product from each of the following. Indicate stereochemistry where appropriate. N - NHPH m“ W50 W of" ""1 on = M (M) X Q M 2. Provide the reagents (over the arrows) needed to effect the following transformations. (a) I. H0“. HM j /' ' t Z am 2. Jon“ amt. cw» OMc 0M4 (b) M I. 097,8” ? \\\\ 2. “7-, k) . .. fi3N03 .W‘, 6r: [:1 [:1 coal»! h,,/\ coon (or H30 +m) m/ 2.Na0Ac,DMF 3- HO'; HZO 4» ffqnas oxid- _ . . . 3. Starting with 1—hexanol, deyise a synthe51s of n-heptyldimethylamme usmg any reagents of your choosing. steps /\/\/\OH ————————————> Férs or J, Soon, Tm” do /\/\/\ » l’w, om: T .. soon z WWI. H30* 4. Compound 'X', which contains no nitrogen, gives the following IR, NMR, and MS data: MS: m/ e (relative intensity) 166 (M"', 5), 164(15), 135(11), 133(33), 129(100), 92(9), 90(27). qu‘ ’5‘ IXI (b) From ALL . the data given, su gest a stru ‘ C‘“ (c) Give the str ctures and chargesr the seven eaks observed in he MS of 'X'. W ( 2’ + ('4 $919 b M Cro e— sm ,5» (,2 1' act 1' (a, macaw»), 2a” f 0 104 a" ' ,a? g n0 31 92 .r :35 c (m); o c: f {'1 - 90 ’ m 55’ 7' u.» I? I? I2? “30004103 5 . 5. When 2S,3R-2,3—dimethyl-3-hydroxypropanoic acid lactone is treated with LAH, a more polar nonracemic product 1 is formed upon workup. Exposure of‘1 to catalytic acid in the presence of cyclohexanone in a reaction flask fitted with a Deana Stark trap and refluxed in toluene leads to final nonracemic product 2. It 5 ‘ R W“ LAH ————> 0 (then 0 workup) (1) Give the complete structure for the starting lactone above (i.e., substituents and appropriate stereochemistry). (2) Provide a structure for product 1 (in the box above). (3) Suggest a structure for product 2 (in the box above). (4) Assign the absolute stereochemistry for each chiral center in 2 and compare with those in the starting lactone. Are they the same? If not, why not? 5 3.0.7..--_W_l¥téh---mqng%.__fl-_uflflmLM”_#__Mlgflm3uak§flfijmm. 6. Conversion of a ketal to a ketone is usually accomplished with aqueous acidic conditions. (e.g., 3 to 4). However, acid hydrolysis is not effective with dithioacetals such as 5. Instead, alkylation on a sulfur atom with methyl iodide in the presence of water achieves the desired result by an otherwise identical cationic mechanism. Provide a mechanism, therefore, by which 5 goes to 4 using the conditions shown. W“ Q13 _" 3 q4 2, 5 Q \ cuss flag 5 an? $05 5+ ron 5 / 7. For the following reaction sequence, excess (x’s) amine is required to consume the acid (HCl) given off in the formation of the amide product. Alternatively, the “Schotten—Baumann” method can be used to minimize loss of this valuable amine. Provide alternative reaction conditions that reflect this method, and a mechanism for the generation of the amide under "Schotten—Baumann ” conditions. + (opt. pure) Alternative reaction conditions: 1 awn.” H mm“ + X's H117 HMO 5 Mechanism: §\ Mug, 4» ‘ I + (34" -v S Dig {gr}, 2. amnc MB cl )0 as I Hot fie . ( Lm‘ H (m =0 ‘9’ N z u» ‘ 8. In each of the following. there‘MAY be an error in the chemistry as shown. If so, in one sentence / phrase, indicate the error. Should the overall process / reaction/ name be correct, insert ’correct’ in the box to the right. (g WW I . (D o 0 “we” a wwd awe «r (’0') 3’ VENst 'l’ Ham tic“ + wsNHL/O o ) 0H 0 (l?) W “#036 N + mo“ | Smel-fiéam & 2. H301“ —————-——————9 (c) com 3. mm cozcum. A 9. EXTRA CREDIT; you must provide the fully correct answer to receive these 20 points). Compound 'Y‘ gives the following IR, NMR, and MS data: MS: m/ e (relative ' intensity) 121(M+, 76), 95(100), 26(44). Suggest the structure for ’Y’. WAVENUMBER CM‘ 300 3000 2500 20000 1500 1300 1100 1000 900 800 700 650 6 . '...__. a: ’ jggfi'gi; ,_ Eiggggggfiagéfifiégégafi =°—.~ = M a—- 111 11 m. HIHII kl: Ii' . II . 11 111 111 Ill 11 M II EQEEEE EEESE ‘=f =—_—_ E —“— =E§ E EEEEEE = 20/211 IYI ...
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3_19_2001 key - NAME CHEMISTRY 130B (B.H. Lipshutz) Final...

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