Halogenation of silyl enol ethers gives haloketones. Silyl triflate is more reactive and also converts ketones to silyl enol ethers. The archetypical reaction is that of the silyl enol ether of cyclohexanone with benzaldehyde. Aromatic imines reacts with an enol ether to a quinoline in the Povarov reaction. The enzyme enolase catalyzes the dehydration of 2-phosphoglyceric acid to the enol phosphate ester. They are also an important intermediate in the formation of silyl enol ether. Avobenzone exists in two tautomeric forms&colon; enol and keto. Triflic anhydride is useful for converting ketones into enol triflates. The keto and enol tautomers of acetylacetone coexist in solution. Electrophilic selanylating reagents can be used in conjunction with enols, enolates, or enol ethers. Phosphoenolpyruvate (2-phosphoenolpyruvate, PEP) is the ester derived from the enol of pyruvate and phosphate. A variety of hydroxylic compounds can add as nucleophiles, forming either enol or ester products. Usually, the keto form is more stable than the enol. Alkylation of the enol with sodium methoxide and 3-dimethylaminopropyl chloride gives benzydamine. It is also used for preparation of enol ethers and related functional groups.