ALDEHYDES AND KETONES

Transcription

1 ALDEHYDES AND KETONES IN WEEK 1, A STUDENT SHOULD BE ABLE TO: 1. Give the IUPAC name given the structure, and draw the structure given the name, of aldehydes and ketones. Also, draw the structure given any of the following common names: formaldehyde, acetaldehyde, benzaldehyde, acetone, acetophenone. 2. Predict the products of reactions giving rise to aldehydes and ketones, given the starting material and reaction conditions. Important reactions include: Oxidation of 1 and 2 alcohols Ozonolysis of alkenes Hydroboration of alkynes Acid-catalyzed hydration of alkynes 3. Predict the products of the reactions of aldehydes and ketones. Important reactions include: Reactions with hydrides (reducing agents such as LiAlH 4 and NaBH 4 ) Reactions with water and alcohols (to form hemiacetals, acetals) Reactions with derivatives of ammonia (to form oximes, semicarbazides, hydrazones, imines, and enamines) Reactions with thiols Oxidation Wolff-Kishner reduction of ketones to alkanes 4. Propose syntheses using the reactions of Objectives #2 and #3. 5. Propose mechanisms of reactions involving nucleophilic attack on the carbonyl carbon. 6. Predict and interpret spectra. IN WEEK 2, A STUDENT SHOULD ALSO BE ABLE TO: 7. Perform the objectives detailed above for these additional reactions with an emphasis on C-C bond forming reactions in synthesis: Friedel-Crafts acylation Reactions with Grignard and organolithium reagents Reactions with ylides (Plus other reactions in the Wittig reaction sequence)

2 To best prepare for this module, please work Chapter 20 Skill Builder problems in the textbook. A STUDENT WHO HAS MASTERED THE OBJECTIVES ON THE PREVIOUS PAGE SHOULD BE ABLE TO SOLVE THE FOLLOWING PROBLEMS AND RELATED ONES: Problems 1-6 should be mastered for the first week of drill: 1.1 Draw each of the following compounds. a) acetaldehyde b) acetophenone c) 2-methylcyclopentanone 1.2 Name each of the compounds shown. 2. Predict the product(s) of each of the following reactions. a) d) 1. O 3 2. Me 2 S

3 2. 3. Predict the product(s) of each of the following reactions.

4 4. Propose syntheses of each of the compounds indicated, from the given starting material and any other needed reagents. a) 3-methyl-1-butanol from trans-5-methyl-2-hexene 5. Propose a mechanism for the following reactions. 6.1 Propose structures for each of the following compounds: (a) C 9 H 10 O 2 IR: 1695 cm -1 1 H NMR spectrum triplet, 1.3 (3H) quartet, 4.1 (2H) doublet, 6.9 (2H) doublet, 7.8 (2H) singlet, 9.9 (1H)

5 6.1 continued (b) C 10 H 12 O IR: 1710 cm -1 1 H NMR spectrum triplet, 1.0 (3H) quartet, 2.2 (2H) singlet, 3.8 (2H) singlet, 7.2 (5H) 7.1 Predict the product(s) of each of these reactions. 7.2 Complete these reactions.

6 7.2 continued e) 1. CH 3 CH 2 Li OH 1. H 2 CrO 4 2. H 3 O + 2. CH 3 OH, H Propose syntheses of each of the compounds indicated. a) benzaldehyde from benzene

7 7.3 continued 7.4 Propose a mechanism for this reaction: SOLUTIONS TO SAMPLE PROBLEMS: 1.1 a) acetaldehyde b) acetophenone c) 2-methylcyclopentanone 1.2 a) 4-methyl-2-pentanone b) 3,3-dimethylcycloheptanone c) 3-chloropropanal

8 2. The reactions give these products: a) b) 1) BH 3 -THF O 2. H 2 O 2,NaOH H 3.

9 4.

10 5. Mechanisms: a) - OCH 3 CH 3 O O + HOCH 3 HO + CH 3 O - OCH 3 basic solution: neutrals and anions, not cations O - H O CH Unknowns: 7.1

11 7.1 continued 7.2 O O a) + Cl AlCl 3

12 7.3 d) (C 6 H 5 ) 3 P + CH 3 CH 2 Br (C 6 H 5 ) 3 P + CH 2 CH 3 Br - (C 6 H 5 ) 3 P + CH 2 CH 3 Br - + NaNH 2 (C 6 H 5 ) 3 P=CHCH 3 (C 6 H 5 ) 3 P=CHCH 3 + C 6 H 5 CH 2 CH=O C 6 H 5 CH 2 CH=CHCH 3 + O=PPh 3

13 7.4 O OMgBr C OCH 2 CH 3 +2CH 3 MgBr C(CH 3 ) 2 + CH 3 CH 2 OMgBr O OMgBr C OCH 2 CH 3 +CH 3 MgBr C OCH 2 CH 3 CH 3 OMgBr O C OCH 2 CH 3 C CH 3 +CH 3 CH 2 OMgBr CH 3 O OMgBr C CH 3 +CH 3 MgBr C(CH 3 ) 2

14 Name Drill Test 6.1 (Sample A) Organic Chemistry 2220D Answer All Questions 1. Draw the structure of: p-nitroacetophenone 2. Give the IUPAC name of: 3. Predict the products of these reactions: a. b. c. d. e. 4. Propose complete mechanisms for these reactions. Include all intermediates and arrows. a. b.

15 5. Propose syntheses for these compounds: a. 2-butanol from 3-methyl-3-heptene b. 6. Draw the structure for a compound that is consistent with these data: IR: 2950 cm -1 ; 1750 cm C NMR: 212, 42, 27, 18 ppm 1 H NMR: 2.6 ppm, septet, 1H; 2.1 ppm, singlet, 3H; 1.1 ppm, singlet, 1H m/z of molecular ion: 86 Name Drill Test 6.1 (Sample B) Organic Chemistry 2220D Answer All Questions 1. What is the IUPAC name of: 2. Draw the structure of: 2,2,2-trichloroacetaldehyde 3. Predict the products of these reactions:

16 3. 4. Propose syntheses. a. benzaldehyde from benzyl chloride b. c. CH 3 CH 2 CH 2 CH=NH from CH 3 CH 2 C CH 5. Draw a mechanism for each of these reactions: 6. Predict the IR and 1 H NMR spectra of 3-pentanone.

17 Name Drill Test 6.2 (Sample A) Organic Chemistry 2220D Answer All Questions 1. Name: O Cl Cl 2. Draw the structure of (a) 1,1-diiodo-3-pentanone (b) 2-hydroxypropanal 3. Predict the product or products (if any) of each of the following reactions. dil H + d) CH 3 CH 2 C CH + HgSO 4, H 2 SO 4, H 2 O

18 4. Propose a synthesis of each of the compounds shown, from the given starting material and any other needed reagents. a) S S from b) from (C 6 H 5 ) 3 PandCH 3 Cl c) O from Br

19 Name Drill Test 6.2 (Sample B) Organic Chemistry 2220D Answer All Questions 1. Which of the following compounds gives a new product on reaction with H 2 CrO 4, and decolorizes Br 2 in CCl 4? 2. Give the IUPAC name for the 3. Draw the structure of following compound. 2,3-dimethylcyclopentanone. 4. Predict the product of each of the following reactions. 5. Propose a synthesis of the compounds indicated from the given starting materials and any other needed reagents.

20 6. Propose a mechanism for the reaction shown. 7. An unknown has the formula C 4 H 6 O and a strong peak in the IR spectrum near 1690 cm -1. The pmr spectrum is: doublet, 2.0, 3H multiplet, 6.1, 1H multiplet, 6.9, 1H doublet, 9.5, 1H Give the structure of this unknown.