Page 409 - Advanced Organic Chemistry Part A - Structure and Mechanisms, 5th ed (2007) - Carey _ Sundberg

390 group is molecular nitrogen. Alkyl diazonium ions can also be generated by nitrosation
of primary amines (see Section 4.1.5). Entry 9 is a reaction of an oxonium ion. These
CHAPTER 4 ions are much more reactive than sulfonium ions and are usually generated by some
Nucleophilic Substitution in situ process.
The reactions illustrated in Scheme 4.1 show the relationship of reactants and
products in nucleophilic substitution reactions, but say nothing about mechanism. In

Scheme 4.1. Representative Nucleophilic Substitution Reactions
A. Neutral reactant + neutral nucleophile R–X + Y: R–Y + + X –
or
R–X + Y–H R–Y + H–X
acetone
+
1 a CH CH I + (n – C H ) P: (n – C H ) P C H I –
3
2
4 9 3
4 9 3
2 5
100%
C H OH
2 5
2 b C H C(CH ) Cl C H C(CH ) OC H + HCl
3 2
6 5
6 5
2 5
3 2
H O 87%
2
3 c CH CHCH CH 3 CH CHCH CH 3 + p–HO SC H CH 3
2
3
3
2
3
6 4
acetone
OTs OH 77%
B. Neutral reactant + anionic nucleophile R–X + Y: – R–Y + X: –
acetone
4 d CH3CHC N + NaI CH3CHC N + NaBr
96%
Br I
5 e CH OTs + LiBr acetone CH Br 94%
2
2
ethanol
6 f CH CH(CH ) CH 3 + NaSC6H5 CH CH(CH ) CH 3
2 5
3
3
2 5
OTs SC H
6 5
C. Cationic reactant and neutral nuclophile R–X + + Y: R–Y + + X
acetonitrile +
+
7 g C H CHS (CH ) + (H N) C = S [C H CH–S–C(NH ) ]
2
2
6 5
6 5
2 2
3 2
CH3 CH 3
+
2 5
–
8 h (C H ) C = N = N + TsOH (C H ) CH–N + N C H OH (C 6 5 2 2 5 2
H ) CHOC H + N
6 5 2
6 5 2
+
D. Cationic reactant and anionic nucleophile R – X + Y: R – Y + X:
+ –
+ –
9 i (C H ) O BF 4 + Na O CC(CH ) (CH ) CCO C H + O(C H )
2 5 2
2 5 3
2 2 5
3 3
3 3
2
90%
NaI
+
10 j CH = CHCH CH S (CH )C H CH = CHCH CH I + CH SC H
6 5
2
2
3
3
2
2
6 5
2
2
DMF
52%
a. S. A. Buckler and W. A. Henderson, J. Am. Chem. Soc., 82, 5795 (1960).
b. R. L. Buckson and S. G. Smith, J. Org. Chem., 32, 634 (1967).
c. J. D. Roberts, W. Bennett, R. E. McMahon, and E. W. Holroyd, J. Am. Chem. Soc., 74, 4283 (1952).
d. M. S. Newman and R. D. Closson, J. Am. Chem. Soc., 66, 1553 (1944).
e. K. B. Wiberg and B. R. Lowry, J. Am. Chem. Soc., 85, 3188 (1963).
f. H. L. Goering, D. L. Towns, and B. Dittmar, J. Org. Chem., 27, 736 (1962).
g. H. M. R. Hoffmann and E. D. Hughes, J. Chem. Soc., 1259 (1964).
h. J. D. Roberts and W. Watanabe, J. Am. Chem. Soc., 72, 4869 (1950).
i. D. J. Raber and P. Gariano, Tetrahedron Lett., 4741 (1971).
j. E. J. Corey and M. Jautelat, Tetrahedron Lett., 5787 (1968).