Solvolysis of Electron-Deficient Norbornyl Triflates 61
Questions
After years of discussion, the nonclassical nature of the 2-norbornyl and 7norbornenyl cations 9 and 15 seems to be beyond doubt and their structure and
charge delocalization is discussed in almost every organic reaction mechanisms
textbook (Figure 9.2).
nonclassical carbocation
norbornyl
7-norbornenyl
nonclassical carbocation
9
15
Figure 9.2
Many other cations (generally obtained from solvolysis reactions) have been
studied and their classical/non-classical nature has been established. Some of them
are shown below in Figure 9.3.
Represent their structures and justify how the positive charge could be stabilized in each case.
Ph
16
classical carbocation
nonclassical carbocation
2-bicyclo-[3.2.1]octyl
17
18
7-norbornenyl
nonclassical carbocation
15
2-phenylnorbornyl
l
i l
b
i
l
b
cyclopropylmethyl
nonclassical carbocation
y p py
y
p py
Figure 9.3
Answer to the Question
Classical carbocation:
17