Definition of "enol"

Since research on the total synthesis of carotenoids began, the enol ether and the aldol condensations have been frequently used for the formation of carbon-carbon double bonds.

1996, Ludvik Labler, August Rüttimann, Alfred Giger, Chapter 2: Coupling Reactions: Part I: Enol Ether and Aldol Condensations, George Britton, Synnove Liaaen-Jensen, Hanspeter Pfander (editors), Carotenoids, Volume 2: Synthesis, Springer (Birkhäuser), page 27

A solution to the use of the thermodynamic ketone enolate lies in the selective formation and reaction of silyl enol ethers.

2004, J. E. Carruthers, W. Carruthers, Iain Coldham, Modern Methods of Organic Synthesis, 4th edition, Cambridge University Press, page 29

It is interesting to note that relative enol stability (pKE) plays little or no role in the relative acidity of enols for example, as in the case of 45 and 45’243.

2009, Jason Eames, “8: Acid-base properties of enols and enolates”, in Jacob Zabicky, editor, The Chemistry of Metal Enolates, Part 1, Wiley, page 421