Really quickly, esters can also be alkylated and acylated. The only catch is that you need to use LDA. You can't use any other base. You can't just use hydroxide. Why do you think it would be a mistake to use OH- on an ester? Can you think of a reason? If you use OH- on an ester, what you're actually going to get is a hydrolysis. You're going to wind up getting a carboxylate. That would be like an SN2 reaction. You don't want your base to react with the alkyl group, same as if I used let's say OR1. If I used an alkoxide base with an R different from the R in my alkyl group, I'm going to get a transesterification. I don't want that to happen. What we do is we use a non-nucleophilic. LDA is considered a non. Let me draw it for you really quick.
LDA, in case you haven't seen it in a while: nitrogen, isopropyl, isopropyl, lithium, this is considered a non-nucleophilic base. Why? Because it has a very hard time can't donate its electrons. Can you see that? Perfect. Sorry, my handwriting sucks down there. But LDA is a non-nucleophilic base. It can't donate its electrons, so it's not going to be able to attack this carbon. Instead, it just reacts as a base and pulls off an alpha hydrogen. By using LDA, we strategically make the enolate and we don't have to worry about any types of carboxylic acid derivative reactions.
By the way, if you haven't studied carboxylic acids yet or if that wasn't your forte, don't worry about that. I don't really care that you know all the details here. If this is the first time you're hearing about transesterification or SN2 or any of that, just focus on the point. The point being, use LDA. For reasons that you don't understand yet, use LDA, and later on, when you get to carboxylic acid derivatives, it will make more sense. LDA makes an enolate, and then you would then do your attack on the alkyl halide or the acid chloride and you would get your products either OR with an R group OR OR with an acyl group. Make sense? Awesome. Pretty straightforward page. Nothing too crazy here. Let's move on to the next page.