_P.-Powell-auth.-Principles-of-Organometallic-Chemistry-Springer-Netherlands-1988

Problems
7. Discuss the use of organoaluminium compounds in organic synthesis.
Exemplify your account by reference to each of the following compounds.
(a)~
(b) ~OH (n=4-6)
(c) (d) C)--0
( e) Isotactic polypropylene
(University College, London).
8. An optically active compound A. C 11 H 18 0, (a= 1685 cm -l) on reaction
with lithium dimethylcuprate gave B, C 12 H 22 0 (11 = 1730 cm -!) and an isomer
C. Reaction of B with meta-chloroperbenzoic acid gave D. C 12 H 22 0 2 , (a=
1745cm- 1 ) converted by lithium aluminium hydride into E. C 12 H 26 0 2 ,
[o:)6 5 o= + 83°. Similar treatment of C gave F. C 12 H 26 0 2 , [o:]6 5 o=+ 17°.
A compound identica! with E in ali respects except for its optica! rotation,
[o:]6 5 o= - 80°, was synthesized as outlined below.
C)
'E'
( i) n-C 4 Hgli
(iil Me,,
HA?
(R)
H 3 0+
o )
G OH+ H
c?H14os2
C12H2202S2
( i ) n-C 4 H9Li
(jj)
~
! OTHP
(R)
J
Raney nickel
1
C22H4204 ethanol C25H4504S2
Identify A and delineate ali the reactions described, with stereochemical detail.
(THP = tetrahydropyranyl.)
(University of Exeter).
97