Lancotrione
Lancotrione is a herbicide, closely related to tefuryltrione. Its mode of action inhibits 4-hydroxyphenylpyruvate dioxygenase, an enzyme which produces homogentisic acid.
It was announced by Ishihara Sangyo Kaisha in 2016, and commercialised in 2019. Lancotrione is a new herbicide, usually used in the form of sodium salt to control grass weeds, in rice crops. As such, little is yet known about it.
Synthesis
It starts from 1-bromo-2,3-dichloro-4-methylsulfonylbenzene,, which is then refluxed with sodium hydroxide in tert-butanol. This is alkylated with 2--1,3-dioxolane under basic conditions,, converted in a palladium-catalysed carbonylation to a methyl ester,. The ester is then saponified, and the consequent benzoic acid derivative,, with O-acylation of 1,3-cyclohexanedione and subsequent cyanide-catalyzed rearrangement, makes lancotrione.