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Unformatted text preview: O + + OR O CH 2 PPh 3 + 3. Cyclopropanone has more bond angle strain than does the corresponding hydrate. The carbonyl carbon is sp 2 hybridized and must have 120° angle. However, in the cyclopropanone ring the angle is 60° leading to a bond angle compression of 120°- 60° = 60°. In the hydrate the carbon is sp 3 hybridized and must have the tetrahedral angle of 109°. The strain is therefore 109°-60° = 49°, which is less than in the corresponding starting ketone. O OH HO H 2 O sp 2 C sp 3 C 4. 4-Hydroxybutanal reacts first to form the cyclic hemiacetal, which being an alcohol, gets oxidized to the carbonyl group. HO O O H O O OH O O PCC 5. .. H O BF 3 H O BF 3 CH 3 —S—H H O BF 3 S CH 3 H H O BF 3 S CH 3 + H + H O BF 3 S CH 3 H H S CH 3 CH 3 —S—H H S S CH 3 CH 3 H H S S CH 3 CH 3 H 2 O + BF 3 + HO—BF 3 + HO—BF 3...
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This note was uploaded on 04/22/2009 for the course CHEM 3570 taught by Professor Ganem, b during the Fall '06 term at Cornell.
- Fall '06
- GANEM, B