Note that no other reagents are needed in
order to complete any of these sequences, you should only be using what is there.
Part A
i This reaction is the hydrolysis of an acetal.
In this scheme, the base, B:, could be R-O-R, R-OH, H2O or the conjugate base of the acid catalyst
ii This is a Friedel-Crafts
alkylation of an aromatic via an electrophilic aromatic substitution
involving a carbocation
rearrangement.
iii This is an acid catalysed transesterification....
the -OH of the molecule displaces the methanol to give the cyclic ester.
In this scheme, the base, B:, could be C=O, R-OH, or the conjugate base of the acid catalyst
Part
B
i LiN(iPr)2 is LDA, a strong base (pKa = 35),
which will form an enolate
of the ester. This enolate will then react with the ketone (similar
to the aldol
reaction). The product of this step contains an alkoxide and there is
a good leaving group (the chlorine) on the adjacent carbon so an intramolecular
Williamson
type reaction - just SN2 - happens to form a cyclic ether, the epoxide
(note : this last step is also like
using a halohydrin
to form an epoxide)