Chapter 17: Carbonyl Compounds II

Transcription

1 Chapter 17: Carbonyl Compounds II Learning bjectives: 1. ecognize and assign names to aldehydes and ketones. 2. Write the mechanism for nucleophilic addition and nucleophilic addition-elimination reactions of aldehydes and ketones, and be able to predict the products of such reactions. 3. Be able to explain the relative reactivity of carbonyl compounds toward nucleophilic addition. 4. Be able to describe the concept of employing protecting groups. 5. Predict the products of the reactions of carbonyl compounds with Grignard reagents, hydride ion donors, sulfur nucleophiles, and with phosphonium ylides (the Wittig reaction). 6. Be able to recognize e and Si faces of carbonyl compounds, and the stereochemistry outcomes from a nucleophilic addition. 7. Predict the products of addition reactions to α,β-unsaturated carbonyl compounds. Sections: 17.1 Nomenclature of Aldehydes and Ketones 17.2 elative eactivities of Carbonyl Compounds* 17.3 ow Aldehydes and Ketones eact* 17.4 eaction of Carbonyl Compounds with Grignard eagents* 17.5 eaction of Carbonyl Compounds with Acetylide Inos 17.6 eaction of Carbonyl Compounds with ydride Ion* 17.7 eaction of Aldehydes and Ketones with ydrogen Cyanide 17.8 eaction of Aldehydes and Ketones with Amines and Derivatives of Amines* 17.9 eaction of Aldehydes and Ketones with Water eaction of Aldehydes and Ketones with Alcohol* Protecting Groups* Addition of Sulfur Nucleophiles The Wittig eaction Forms an Alkene* Stereochemistry of Nucleophilic Addition eactions: e and Si Faces # Designing a Synthesis VI: Disconnections, Synthones, and Synthetic Equivalents Nucleophilic Addition to α,β-unsaturated Aldehydes and Ketones* Nucleophilic Addition to α,β-unsaturated Carboxylic Acid Derivatives Enzyme-catalyzed Additions to α,β-unsaturated Carbonyl Compounds # * Sections that will be focused # Sections that will be skipped ecommended additional problems , , , ,

2 Class Note 17.1 Nomenclature of Aldehydes and Ketones Cl C 2 C 3 C 2 C 3 C 2

3 C 3 3

4 17.2 elative eactivities of Carbonyl Compounds* Nucleophilic addition 17.3 ow Aldehydes and Ketones eact* A. In basic condition Nu Nu () () () Nu ( Z) tetrahedral intermediate 4

5 B. In acidic condition B B + B () () () 5

6 17.4 eaction of Carbonyl Compounds with Grignard eagents* A. Carbon nucleophile (basic or acidic?) B. eaction of aldehydes and ketones with Grignard reagent 6

7 C. eactions of ester and carboxylic acid with Grignard reagent 7

8 17.5 eaction of Carbonyl Compounds with Acetylide Inos (i) pka of C 2 C 2 C C C C (ii) Mechanism 8

9 17.7 eaction of Aldehydes and Ketones with ydrogen Cyanide (i) pka of -CN (ii) Mechanism (iii) Synthesis of α-hydroxy carboxylic acid 9

10 17.6 eaction of Carbonyl Compounds with ydride Ion* A. Source of hydride B. eduction of aldehydes and ketones 10

11 C. eduction of esters 11

12 D. eduction of carboxylic acids 12

13 E. eduction of amides 13

14 17.8 eaction of Aldehydes and Ketones with Amines and Derivatives of Amines* A. pka of amines B. Addition of primary amines 14

15 C. Addition of secondary amines D. Addition of hydrazine, hydroxyamine 15

16 E. Mechanism of Wolff-Kishner reduction 16

17 17.9 eaction of Aldehydes and Ketones with Water A. Addition of water (formation of hydrate, gem-diol, geminal diol) () () 2 (i) Consideration of pka (ii) Stability consideration 17

18 17.10 eaction of Aldehydes and Ketones with Alcohol* A. Addition of alcohol (formation of hemiacetal, acetal, hemiketal, and ketal) ' ' ' ' (2 equivalents) 2 ' ' ' ' (2 equivalents) 2 18

19 C. Mechanism 19

20 17.11 Protecting Groups* A. Stability of acetals and ketals B. Example + C 2 C (i)? C 3 20

21 C. More examples (i) N 2? N 2 N 2 (ii) N 2? N 2 C 2 21

22 17.12 Addition of Sulfur Nucleophiles The Wittig eaction Forms an Alkene* A. Wittig reagents (C 6 5 ) 3 P C 2 phosphonium ylide (C 6 5 ) 3 P C 2 B. Formation of Wittig reagents 22

23 C. eactions (i) Synthesis of (ii) Synthesis of 23

24 D. Stereoselectivity (E vs. Z) E. Arbuzov (Perkow) reaction and orner-emmons reaction (i) orner-emmons reaction 24

25 (ii) Arbuzov (Perkow) reaction 25

26 17.15 Designing a Synthesis VI: Disconnections, Synthones, and Synthetic Equivalents A. etrosynthetic analysis Example synthesis of from 26

27 17.16 Nucleophilic Addition to α,β-unsaturated Aldehydes and Ketones* A. Analysis of α,β-unsaturated aldehydes and ketones β α B. Direct addition (1,2-addition) and conjugate addition (1,4-addition) 27

28 C. Examples (i) 1) CN 2) Cl (ii) + SC 3 (iii) + (C 3 ) 2 N C 3 28

29 (iv) 1) NaB 4, CeCl 3 2) 2, + (v) 1) C 3 MgBr 2) 2, + (vi) 1) C 3 MgBr 2) 2, + 29

30 (vii) 1) (C 3 ) 2 CuLi 2) 2, Nucleophilic Addition to α,β-unsaturated Carboxylic Acid Derivatives Cl + C 3 NC 3 + C 3 1) LiAl 4 2) 2, + C 3 Cl + N 3 (excess) 30