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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 SH 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 SH H S S CH 3 CH 3 H H S S CH 3 CH 3 H 2 O + BF 3 + HOBF 3 + HOBF 3...
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- Fall '06
- GANEM, B