1559T_ch17-304-32211/3/0510:48Page310 EQA 310.Chapter 17 ALDEHYDES AND KETONES:THE CARBONYL GROUF 25.(a)CrO3.HSO acetone,or MnO2.CH2Cla (better): (b)PCC.CH2Clz;(e)1.O3.CH2Cl2,2.Zn,CHaCOOH,H2O: (d)HgSO.HaO.HSO:(e)same as (d) mO8aa.2ra 26.QLGLGLG+Gi2○d 27.(a)Ask"How electrophilic is the carbon in question?" (CH3)C-H(CHa)C-O(CH3)C-NH Onder of ketone and imine detemined by clectronegativity 000 0 (b)CH.CCCCH,>CH.CCCH,>CH,CCH, 二 29.a01 (c) HO OCHs 31.a〔 The starting material cquilibrates with this product. 25. (a) CrO3, H2SO4, acetone, or MnO2, CH2Cl2 (better); (b) PCC, CH2Cl2; (c) 1. O3, CH2Cl2, 2. Zn, CH3COOH, H2O; (d) HgSO4, H2O, H2SO4; (e) same as (d); (f) 1. 2. H
H2O O O B B 26. (a) CH3CH2CH2CH
HCH (b) O O B B (c) HCCH2CH2CH2CH2CH (d) 27. (a) Ask “How electrophilic is the carbon in question?”: (CH3)2CPO
H (CH3)2CPO (CH3)2CPNH Order of ketone and imine determined by electronegativity. OOO OO O BBB BB B (b) CH3CCCCH3 CH3CCCH3 CH3CCH3 Adjacent carbonyl groups enhance each other’s reactivity by reinforcing the 
character of their respective carbons. (c) BrCH2CHO CH3CHO BrCH2COCH3 CH3COCH3 Aldehydes are more reactive than ketones; halogen substituents increase reactivity. 28. (a) (b) (c) 29. (a) (b) (c) 30. (a) (b) (c) 31. (a) The starting material equilibrates with this product. HO OCH3 OH O O OH O O OH OH H O O OH OH H O O 2 O C Cl, AlCl3, O 310 • Chapter 17 ALDEHYDES AND KETONES: THE CARBONYL GROUP 1559T_ch17_304-322 11/3/05 10:48 Page 310