Substituted 2-oxo-3-alkynoic acids and methods of use thereof

A herbicidal composition comprising a herbicidally effective amount of a compound having the formula:

• wherein R represents H or the residue of a protecting group;
• R′ represents R″ (CH2)n—, wherein R″ is selected from the group consisting of hydrogen or halogen, or R′ represents unsubstituted or substituted phenyl (C6H5), wherein the phenyl substituent is at least one selected from the group consisting of fluorine or trifluoromethyl;
• and n is an integer from 0-4, or an agriculturally suitable salt of the acid form of said compound, and a carrier medium.