Illustrated Glossary of Organic Chemistry

Ethoxide (ethoxide ion; EtO^-): CH₃CH₂O^-; the conjugate base of ethanol. A strong base (frequently used in E2 and enolate reactions) and a good nucleophile.

Structure of ethoxide ion.

		+
	2-Methyl-2-butene Internal trisubstituted alkene Major product		2-Methyl-1-butene Terminal disubstituted alkene Minor product

Sodium ethoxide as a base in an E2 reaction, illustrating Zaitsev's rule.


Potassium ethoxide as a nucleophile in a Williamson ether synthesis (an S_N2 reaction).