Enolates are usually formed through the deprotonation of a carbonyl compound, such as an aldehyde, ketone, or ester. This deprotonation is typically facilitated by a base. The choice of base and the reaction conditions can significantly influence the formation of the enolate and its subsequent reactivity. Common bases used include lithium diisopropylamide (LDA), sodium hydride (NaH), and potassium t-butoxide (KOtBu).