Organic Chemistry

Problems 397

2. reaction: a two-step mechanism with a carbocation intermediate

Relative reactivities of alkyl halides:

Both the inverted and noninverted products are formed.

3 ° 72 ° 71 ° 7 CH 3 X.

−

Nu

CCX C+

X−

Nu

+

SN 1

Key Terms

aprotic solvent (p. 389)

back-side attack (p. 363)

base (p. 368)

basicity (p. 368)

bimolecular (p. 000)

complete racemization (p. 381)

dielectric constant (p. 389)

elimination reaction (p. 360)

first-order reaction (p. 376)

intimate ion pair (p. 381)

inversion of configuration (p. 366)

ion–dipole interaction (p. 369)

kinetics (p. 362)

leaving group (p. 360)

Le Châtelier’s principle (p. 373)

nucleophile (p. 368)

nucleophilicity (p. 368)

nucleophilic substitution reaction (p. 362)

partial racemization (p. 381)

protic solvent (p. 389)

rate constant (p. 362)

rate law (p. 362)

second-order reaction (p. 362)

reaction (p. 376)

reaction (p. 363)

solvolysis (p. 379)

steric effects (p. 364)

steric hindrance (p. 364)

substitution reaction (p. 360)

unimolecular (p. 376)

SN 2

SN 1

Problems

32. Give the product of the reaction of methyl bromide with each of the following nucleophiles:
    a. b. c. d. e. f.


33. a. Indicate how each of the following factors affects an reaction:
    b. Indicate how each of the following factors affects an reaction:
    
    
    1. the structure of the alkyl halide 3. the concentration of the nucleophile
    
    
    2. the reactivity of the nucleophile 4. the solvent
    
    
    
    


34. Which is a better nucleophile in methanol?
    a. or c. or e. or
    b. or d. or f. or


35. For each of the pairs in Problem 34, indicate which is a better leaving group.


36. What nucleophiles could be used to react with butyl bromide to prepare the following compounds?

NH 3 - NH 2 HO- HS- Cl- Br-

H 2 O HO- H 2 O H 2 S I- Br-

SN 2

SN 1

HO- -NH 2 H 2 S HS- CH 3 O- CH 3 NH 2

a.

b.

c.

d.

e.

f.

g.

h. CH 3 CH 2 CH 2 CH 2 C‚CCH 3

CH 3 CH 2 CH 2 CH 2 OCCH 3

O

CH 3 CH 2 CH 2 CH 2 C‚N

CH 3 CH 2 CH 2 CH 2 NHCH 3

CH 3 CH 2 CH 2 CH 2 SCH 2 CH 3

CH 3 CH 2 CH 2 CH 2 SH

CH 3 CH 2 CH 2 CH 2 OCH 3

CH 3 CH 2 CH 2 CH 2 OH

37. Rank the following compounds in order of decreasingnucleophilicity:

a. c. and in methanol

b. d. in methanol

38. The of acetic acid in water is 4.76 (Section 1.17). What effect would a decrease in the polarity of the solvent have on the
    Why?

pKa pKa?

O− and O− in DMSO Br-, Cl-, I-

CH 3 CO H 2 O NH 3

−,CH

3 CH 2 S

−,CH

3 CH 2 O

−

O

(^) in methanol
AU: Not boldfacein text. Fix there or delete here.