W03 problems4b key

W03 problems4b key - O H(less stable cation O H OH...

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OH OMs OH TfO THF I OH 1-propanol ether O Problem Set 4 (Chapter 11 Ethers) TA: Danny Ng 2/3/2003 2. Provide the r e a g e n t s or p r o d u c t s for the following reactions. Pay attention to stereochemistry if applicable. 1. Provide the structures for the following compounds. Pay attention to stereochemistry if applicable. a) Isobutyl tert -butyl ether b) trans -4-ethoxycycloheptanol c) 3 R-tert- butoxy-5,7-nonadiyne d) cis -2-mercaptocyclohexyl phenyl ether e) trans -2,3-diethynyl-oxetane f) 2 R -methyl-tetrahydropyran a) 1. K 0 2. b) 1. Butyllithium 2. c) LDA d) HCl (dilute) e) HBr (dilute) 25 o C O HO O O SH O O O OH O O O O OH Br OH Br
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OH Ph O H 3 CO O NaCN OH O O O O O TA: Danny Ng 2/3/2003 Problem Set 4 (Chapter 11 Ethers) f) menthol g) m -CPBA h) 1. Br 2 , H 2 O 2. NaOH i) NaOH, H 2 O H 3 O + , H 2 O 3. Explain the following results with reaction mechanisms. a) , H 2 SO 4 MAJOR H 2 SO 4 Ph O Ph O O O H 3 CO O - Na + OH acidic workup H 3 CO OH OH H 3 CO OH OH HO H 3 CO OH H 3 CO O - Na + CN acidic workup H 3 CO OH CN O H OSO 3 H O H (more stable cation - resonance)
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Unformatted text preview: O H (less stable cation) O H OH MAJOR (racemic) (single isomer) (single isomer) O R OH O O HO O Ph HO O H 2 SO 4 O I I Ph Cl OH O OTs O HO TA: Danny Ng 2/3/2003 Problem Set 4 (Chapter 11 Ethers) b) m-CPBA c) HI, heat 4. Synthesis. a} Draw the structures for the intermediates and final product. Pay attention to stereochemistry 1. NaNH 2 2. H 3 O, H 2 O + b) Provide the reagents to achieve the following transformation. O H O O Cl O O O Cl H H I O Ph H I O Ph H I H I O Ph H I H I O O O O O O O O HO Retro-synthesis: O HO HO H H HO HO I needs to be protected cis Forward HO O HO 1. H 2 SO 4 2. NaNH 2 3. 1-iodobutane (OH protection) 4. H 3 O + /H 2 O (OH deprotection) 5. H 2 /Lindlar’s cat. 6. m-CPBA...
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W03 problems4b key - O H(less stable cation O H OH...

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