Method of producing L-glufosinate

A method for preparing L-glufosinate from an L-homoserine compound of the following Chemical Formula 1, the method comprising a step a of preparing a compound of the following Chemical Formula 2 from the compound of the following Chemical Formula 1, and a step b of preparing a compound of the following Chemical Formula 3 from the compound of Chemical Formula 2,

• wherein the step a comprises a step a-1 of preparing the compound of Chemical Formula 2 by reacting the compound of Chemical Formula 1 with a halogenating agent, at least one R2—OH, and a compound of the following Chemical Formula 5,
• where in the above formulas,
• R1 is Ra—(C═O)—, where Ra is hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkenyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkynyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 10 carbon atoms,
• R2 is hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkenyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkynyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 10 carbon atoms, or —Si(Rb)(Rc)(Rd), where Rb, Rc and Rd independently of one another are a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms,
• R3 and R4 independently of one another are hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkenyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkynyl group having 1 to 6 carbon atoms,
• R5 is hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkenyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkynyl group having 1 to 6 carbon atoms, and
• substituents of the alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aryl group, and heteroaryl group independently of one another are at least one selected from hydrogen, halogen, a carboxyl group (—COOH), an amino group (—NH2), a nitro group (—NO2), a cyano group (—CN), an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms.