Unformatted text preview: . A good explanation should require no more than 2 or 3 sentences! (a) A : B : I C N Na CH 3 OH solvent N I C N Na DMF solvent N Explanation: (b) A : B : Br CH 3 H 2 O (solvent) CH 3 Cl CH 3 H 2 O (solvent) CH 3 Explanation: S N 1 S N 2 E1 E2 A B S N 1 S N 2 E1 E2 A B Substitution on 1° substrate must occur via S N 2. S N 2 is favored in polar aprotic solvents (like DMF, which cannot form hydrogen bonds to anions) and disfavored in protic solvents (like CH 3 OH, which can form hydrogen bonds to anions), so B should be faster. Elimination on 3° substrate with weak base consistent with E1. A should be faster because Br – is a better leaving group (weaker base) than Cl – ....
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- Spring '05
- Solvent, Tetrahydrofuran, Protic solvent, DMF