Midterm 2 - following synthesis using the Wittig reaction....

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page 1 Midterm 2 Chem 0320 9:00 AM–9:50 AM March 5, 2008 Answer Keys 1. Propanal shows a triplet at 9.8 ppm in its 1 H NMR spectrum. Which hydrogen(s) are responsible for this signal? H O 2. Provide reagents. (a) R 2 BH; then H 2 O 2 , NaOH (R = alkyl or H) (b) (2 steps) 1. LiN i Pr 2 , PhSeCl; 2. H 2 O 2 H O O O (c) Br 2 , NaOH (d) LiAlH 4 ; then D 2 O O CBr 3 O OH O OD (e) Mg; then CO 2 ; then H 3 O + Br CO 2 H 3. Show the major product(s) of each of the following reactions. (a) (b) HO HO OH O H 2 SO 4 + O O OH OOH O O O O (c) (d) O NH 2 NH 2 , KOH heat O HCN CN HO
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page 2 (e) (f) (Specify relative stereochemistry) O LiN(CHMe 2 ) 2 ; then CH 2 =CHCH 2 Cl O O Ph 2 CuLi; then CH 3 Br O Ph CH 3 (g) (aldol; no E1cb) (h) (acid-base reaction) CHO + O NaOH OH O O OH + NaOMe O ONa + MeOH 4. Provide missing reagents and the structures of the phosphonium salt and ylide to complete the
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Unformatted text preview: following synthesis using the Wittig reaction. Br phosphonium salt ylide PPh 3 Br-PPh 3 H O Ph 3 P base (e.g. NaOH, NaH, LDA) 5. Choose the most acidic carboxylic acid. O OH MeO O OH O OH O 2 N 6. Show the mechanism of the following reactions. (a) N H 3 C H 2 O, H 2 SO 4 O + CH 3 NH 2 N H 3 C H + N H 3 C H O H H H 3 CHN O H H H 3 CHN O H H + H 3 CH 2 N O H O O H + CH 3 NH 2 page 3 (b) N MeI, H 2 O H O N H O I CH 3 N O H H N O H H N O H H + N O H H H O H (c) O D 3 O + O D O D + O D H O D D + O D D O D (d) H 2 SO 4 + excess MeOH O OH O OMe O OH H + O OH H OH OH O H Me OH OH O Me H + OH OH 2 O Me O OMe H O OMe MeOH...
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This test prep was uploaded on 04/07/2008 for the course CHEM 0320 taught by Professor Kazunorikoide during the Spring '08 term at Pittsburgh.

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Midterm 2 - following synthesis using the Wittig reaction....

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