Process of the preparation of chiral nicotinic, quinolinic or benzoic acid imidazolinone herbicides

Imidazolinone compounds, for instance, those described in U.S. Pat. Nos. 4,188,487; 4,798,619 and 5,334,576, are highly potent, broad spectrum, environmentally benign, herbicidal agents. In general, the herbicidal activity of the R-isomer is better than that of the racemic imidazolinone compound. A process to prepare chiral imidazolinones via the resolved optically active 2-amino-2,3-dimethylbutyramide enantiomers is described in U.S. Pat. No. 4,683,324. Said aminoamide enantiomers are prepared via the hydrolysis of their chiral 2-amino-2,4-dimethylbutyronitrile precursors and are difficult to isolate. There is provided a stereospecific process for the preparation of essentially enantiomerically pure imidazolinone herbicides having the R-configuration via (R) -amino--dimethylbutyronitrile.