L Le ev ve el l 3 3 – – C Ca as se e 4 40 0
S So ol lv vo ol ly ys si is s o of f 8 8- -D De el lt ta ac cy yc cl ly yl l B Br ro os sy yl la at te es s
K Ke ey y p po oi in nt t: : N No No No No N Non nc cl la la l la l la la l las ss si ic ic ic ic i i a al l c ca at ti ti ti t ti ti t tio io io io i ion ns s
OBs
solvolysis of
S So ol lv vo ol ly ys si is s o of f 8 8- -D De el lt ta ac cy yc cl ly yl l B Br ro os sy yl la at te es s
The deltacyclane system 1 has a fusion of nortricyclane and norbornane skeletons
and is an interesting substrate to study skeletal rearrangements or V-bond participations in solvolysis processes.
X
1
2
3
4
5
6
7
8
9
X = leaving group
1
nortricyclane
In this context, the acetolysis of exo- and endo-brosylates 2 (brosylate = p-toluenesulfonate) has been studied.
OBs
exo-2
endo-2
OBs
Considering the following experimental results discuss the mechanism of acetolysis for both epimers. Which type of cations are involved in the processes?
E Ex xp pe er ri im me en nt ta al l D Da at ta a
1. Acetolysis of exo- and endo-brosylates 2 gave a single product, exo-acetate 3.
No endo-substituted products were found (Scheme 40.1).