Exercício de Química Sintética e Organica Mista (197)

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(h) The first reaction is one in which a substituted alcohol is converted to a p-toluenesulfonate
ester. This is followed by an SN2 displacement with lithium iodide.
8.20 The two products are diastereomers of each other. They are formed by bimolecular nucleophilic sub-
stitution (SN2). In each case, a good nucleophile (C6H5S
�) displaces chloride from a secondary
carbon with inversion of configuration.
(a) The trans chloride yields a cis substitution product.
(b) The cis chloride yields a trans substitution product.
8.21 The isomers of C4H9Cl are:
The reaction conditions (sodium iodide in acetone) are typical for an SN2 process.
2-Chlorobutane
(sec-butyl chloride)
2-Chloro-2-methylpropane
(tert-butyl chloride)
CH3CCl
CH3
CH3
CH3CHCH2CH3
Cl
1-Chlorobutane
(n-butyl chloride)
1-Chloro-2-methylpropane
(isobutyl chloride)
CH3CH2CH2CH2Cl CH3CHCH2Cl
CH3
cis-4-tert-Butylcyclohexyl
chloride
C(CH3)3
Cl
trans-4-tert-Butylcyclohexyl phenyl
sulfide
S
C(CH3)3�
Sodium
benzenethiolate
NaS
� SNa
Sodium
benzenethiolate
trans-4-tert-Butylcyclohexyl 
chloride
C(CH3)3
Cl
cis-4-tert-Butylcyclohexyl phenyl sulfide
S
C(CH3)3
CH2CH2CH2CH2OTsCH3O
CH3O
CH2CH2CH2CH2ICH3O
CH3O
OCH3
OCH3
TsCl
pyridine (62%)
LiI, acetone (88%)
OCH3
CH2CH2CH2CH2OHCH3O
CH3O
4-(2,3,4-Trimethoxyphenyl)-1-butanol
4-(2,3,4-Trimethoxyphenyl)-1-butyl iodide
192 NUCLEOPHILIC SUBSTITUTION