Synthesis and herbicidal activity of optically active α-(substituted phenoxyacetoxy) (substituted phenyl)
Chao Xu1, Yuan Zhou1, Ruilin Qi1
1Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, PR China.
Researchers explored chiral differences in herbicidal activity for novel phosphonates. They found specific enantiomers, like (S)-IB7, exhibit significantly higher efficacy against weeds, suggesting potential for more targeted herbicide applications.
Area of Science:
- Agrochemicals
- Organic Chemistry
- Enzyme Inhibition
Background:
- α-(Substituted phenoxyacetoxy) alkylphosphonates show herbicidal activity.
- Investigating chiral differences in herbicidal efficacy is crucial for developing targeted agrochemicals.
Purpose of the Study:
- To explore synthetic methods for optically active substituted phenylalkylphosphonates.
- To evaluate and compare the herbicidal activities of (R) and (S) enantiomers of novel phosphonates.
Main Methods:
- Developed an enantioselective hydrophosphonylation using Schiff base Al(III) complexes.
- Synthesized novel O,O-dimethyl α-(substituted phenoxyacetoxy)(substituted phenyl)methylphosphonates with high enantioselectivity (95-99% ee).
- Evaluated post-emergence herbicidal activities against dicotyledonous plants in greenhouse trials.
Main Results:
- All synthesized compounds (IB) demonstrated significant inhibitory activity against dicotyledonous plants.
- Chiral selectivity in herbicidal effect was observed among racemate, (R), and (S) enantiomers.
- (S)-IB7 showed the highest efficacy against chickweed, with 8.17 times greater activity than (R)-IB7.
Conclusions:
- Optically active phosphonates exhibit differential herbicidal activities based on their stereochemistry.
- (S)-IB7 is a highly effective enantiomer against chickweed, indicating its potential as a potent herbicide.
- Future applications may involve lower application rates for specific enantiomers, enhancing efficiency and reducing environmental impact.
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