Acetate as a Synthetic Equivalent of Hydroxide

In order to promote an Sn2 mechanism at a nonallylic 2° carbon, a different nucleophile is needed, such as acetate (AcO ). Since acetate is resonance stabilized, it is a weaker base than hydroxide, and the E2 elimination mechanism is minimized. 

Substitution with acetate indeed replaces the leaving group with an oxygen atom, but it gives an ester product hydrolysis of the ester affords the desired alcohol TM. 

This two-step synthesis (substitution followed by hydrolysis) is an effective strategy for replacing a 2° leaving group with a hydroxyl. Since acetate can be converted to a hydroxyl group, it is described as a synthetic equivalent of hydroxide many such synthetic equivalents are employed in organic synthesis and will be described in this book. 

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