Note that no other reagents are needed in
order to complete any of these sequences, you should only be using what is there.
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
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
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)
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