Current status of chirality in agrochemicals

Abstract

The agrochemical industry is searching continuously for new pesticides to develop products that have optimal efficacy, lower application rates in the field, increased selectivity, favourable toxicological and environmental safety, enhanced user friendliness and better economic viability. One strategy by which to achieve these ambitious goals makes use of the unique properties of molecules containing asymmetric centres. In the past, many natural products and their congeners have been a source of inspiration in the design of new active ingredients, and the molecular structures of the resulting compounds have become increasingly complex; some 30% contain fragments with asymmetric centres. However, despite enormous progress in catalytic asymmetric processes over the past decade, few agrochemicals are produced in an enantiomerically pure or enriched form on an industrial scale. Since 2007, ∼ 43% of the 44 products launched (insecticides, acaricides, fungicides, nematicides and herbicides) contain one or more asymmetric centres in the molecule (∼ 47%) and most have been launched as racemic mixtures of enantiomers or diastereomers. This review provides an overview of the current status of chiral agrochemicals launched over the past 10 years and describes the inherently connected challenges of modern agricultural chemistry by managing important aspects resulting from the stereochemistry of these innovative products. © 2018 Society of Chemical Industry.

Engineering the Active Site of an (S)‐Selective Amine Transaminase for Acceptance of Doubly Bulky Primary Amines

“…Chiral amines represent an important motif in many groups of fine chemicals, including pharmaceuticals [1] and agrochemicals. [2] To ensure high purity of these compounds, synthetic methods need to be very selective towards the desired enantiomer. Many approaches have been developed towards this goal, both chemo-and biocatalytic ones.…”

Stereoselective bioactivity, toxicity and degradation of the chiral triazole fungicide bitertanol

“…With the development of innovative pesticides, the proportion of chiral pesticides in commercial products has increased rapidly. 1 One of the most notable features is that most chiral pesticides are manufactured and used as racemates. 2 Different enantiomers show similar physicochemical properties in an achiral condition but different activities in a chiral condition.…”

Efficacy of afidopyropen against soybean aphid (Hemiptera: Aphididae) and toxicity to natural enemies

“…A novel pyropene insecticide, afidopyropen (Group 9D), which received registration from the United States Environmental Protection Agency (US EPA) for use in soybean in 2018, may prove an effective insecticide for management of A. glycines by offering an alternative insecticide group for resistance management as well as providing selectivity to conserve natural enemies. This insecticide is a semi‐synthetic derivative of a fermentation product called pyripyropene, which is produced by the microbe Aspergillus fumigatus Fresenius (Eurotiales: Trichocomaceae) . Afidopyropen acts on the vanilloid‐type transient receptor potential (TRPV) channels of the chordotonal stretch receptor neurons of insects .…”

“…This insecticide is a semi-synthetic derivative of a fermentation product called pyripyropene, which is produced by the microbe Aspergillus fumigatus Fresenius (Eurotiales: Trichocomaceae). [33][34][35] Afidopyropen acts on the vanilloid-type transient receptor potential (TRPV) channels of the chordotonal stretch receptor neurons of insects. 36,37 Chordotonal receptors serve a mechanosensory role in insects by detecting movement at articulations.…”