Unformatted text preview: 3/19/2010 Biosynthesis of cholesterol. What is the mechanism of the following reaction?
O O CoA CoA S S thiolase O O S CoA + CoA-SH CoA- H H HO
O H H S H CoA Χ
O CoA S A strategy for drug development A B C What carbonyl reactant would undergo an aldol reaction with 1 to give 2?
O CoA S thiolase O O What carbonyl reactant would undergo an aldol reaction with 1 to give 2?
O CoA S O O S CoA + CoA-SH CoA- A
S O 1 CoA + CoA-SH CoAS thiolase 3-hydroxy-3methylglutarylCoA synthetase (aldol reaction)
+ CoASH 3-hydroxy-3methylglutarylCoA synthetase B C + CoASH 3-hydroxy-3methylglutarylCoA reductase CoA 2 Lipitor
H H HO H cholesterol Which of the following reactions would be best suited for performing this transformation?
March 2, 2010, Evolution Evolution by the Grassroots By OLIVIA JUDSON ?
helminthosporal ? carvomenthone 1 3/19/2010 O O H O H O O H O O H O O O ? ? Why not use OH to make anion? Why not use this anion for the conjugate addition? O H ?
O ? aldol Wittig helminthosporal What is the mechanism of this last reaction? O O H H OH O How can an aldehyde be prepared from a ketone using the Wittig reaction? H O O H aldol O Wittig O Wittig 2 3/19/2010 Which of these Wittig reaction sequences would give an aldehyde? OEt Ph3P C OEt O H3O H O A B O Wittig O H Ph3P C H O H3O H O C What is the next step?
H Ph3P C OEt OEt O C H A
HO H OH H C O O O Wittig B The total synthesis of helminthosporal
H Ph3P C OEt OEt Give an explanation for the following observations. O C H HO H OH H C O O O H O O 3 3/19/2010 The initial product is not acetone. What is it? Give an explanation for the following observations. A B C O H O O ? O H O O 4 ...
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