# Stability of extended enolates

I'd expect an extended enolate to be more stable than a normal enolate, when both can form, but my textbook suggests otherwise.

What is the stability of an extended enolate compared with a normal enolate? For example, following an enolate alkylation of the molecule depicted below, which product ($\alpha$- or $\gamma$-alkylated) will form?

• It might be beneficial if you could provide a reference to your textbook. – andselisk Dec 15 '17 at 19:12
• It probably depends on the deprotonation conditions – orthocresol Dec 15 '17 at 22:16
• @orthocresol Thanks! But could you please elaborate? Do you mean bulkiness of the base? How could you favour one product over the other? – GingerBadger Dec 15 '17 at 22:18
• I was looking for a post, because it has been discussed here before, and I found it: chemistry.stackexchange.com/a/43024/16683 – orthocresol Dec 15 '17 at 22:20
• With LDA for example you can form a six-membered TS (Ireland model) with a $\ce{C=O...Li}$ interaction. I've heard that the model is a simplification of the truth, but the bottom line is that there's probably some kind of involvement of the carbonyl group. – orthocresol Dec 15 '17 at 22:25