Prepd by the reaction between an ether soln of ethyl butyrate and sodium or potassium: Bouveault, Locquin, Bull. Soc. Chim. [3] 35, 629 (1906); Corson et al., J. Am. Chem. Soc. 52, 3988 (1930); Scheibler, Emden, Ann. 434, 265 (1923); Snell, McElvain, Org. Synth. coll. vol. II, 114 (1943).