Method for preparing glufosinate or analogue thereof

A process for preparing glufosinate or its analogues of formula (IV), characterized in that,

• the process comprises:
• a) reacting a compound of formula (II), an alcohol of formula (III) and a compound of formula (V), and
• b) subjecting products obtained from the above reaction to a hydrolysis, to obtain the glufosinate or its analogue of formula (IV),
• wherein R1 and R2 are each independently selected from C1-C16 alkyl, C6-C12 aryl, C3-C10 cycloalkyl, C7-C12 alkaryl and C7-C12 aralkyl, each group being unsubstituted or substituted by C1-C6 alkyl, C1-C6 alkoxy, dialkyl or dialkylamino;
• Hal1 is halogen;
• Hal2 is halogen,
• PG is hydrogen or an amino-protecting group, wherein when PG is the amino-protecting group, the process further comprises removing the amino-protecting group, and
• X is —OR3 or —NR3R4, wherein R3 is C1-C16 alkyl, C6-C16 aryl, C3-C16 cycloalkyl, C7-C16 aralkyl or C7-C16 alkaryl, wherein the groups are each unsubstituted or substituted by C1-C6 alkyl;
• and R4 is hydrogen or as defined for R3;
• and wherein the molar ratio of the compound of formula (II) and the alcohol of formula (III) in the process is 1:(0.1-1.1).