Organic chemistry - Chapter 9: Alkyl halides - Nam Phan

Nội dung text: Organic chemistry - Chapter 9: Alkyl halides - Nam Phan

1. Chapter 9: ALKYL HALIDES 2
2. Alkyl & halogen substituents are considered of equal rank 4
3. Alkyl halides from alkenes More stable 6
4. REACTIONS OF ALKYL HALIDES Very reactive Very unreactive With the same R 8
5. Stereochemistry of SN 2 reactions • The nucleophile attacks from the back side / the side directly opposite the leaving group • This attacks causes an inversion of configuration 10
6. Stereochemistry of SN 1 reactions 12
7. Factors affecting the rates of SN1 & SN2 1. The structure of the substrate 2. The concentration & reactivity of the nucleophile 3. The reaction solvent 4. The nature of the leaving group 14
8. ROH, HOH 22
9. Affects of leaving group The best leaving groups are those that become the most stable ions after they depart The best leaving groups are weak bases 26
10. Functional group interconversions of 1o & 2o alkyl halides Elimination reactions will occur for 3o alkyl halides 28
11. Williamson ether synthesis 30
12. ELIMINATION REACTIONS In an elimination reaction: + Groups / atoms are eliminated from a reactant + A double bond is formed between the 2 carbons from which atoms are eliminated 32
13. Regioselectivity of E2 reactions Zaitsev’s rule for an E2 reaction: more substituted alkene is normally obtained 34
14. In some E2 reactions, the less stable alkene is the major product due to steric effects Zaitsev’s product Hofmann’s product 36
15. Rearrangements in E1 & SN 1 38
16. GRIGNARD REAGENTS Strong base Strong nucleophile 42
17. Reactions of Grignard reagents with aldehydes & ketones Only for the reaction of HCHO 44
18. Reactions of Grignard reagents with esters Can NOT be isolated 48
19. Reactions of Grignard reagents with nitriles 50
20. Reactions of Grignard reagents with epoxides 52