Constrution and Insecticidal Activities of Trifluoromethylated Benzocyclicsulfoximine Derivatives by [3+2] Cycloaddition Reaction of Beznyne

Sulfoximines derivatives are widely used in the field of pesticides and medicine due to its antimalarial, antibacterial and herbicidal properties. A concise and direct synthetic strategy for the construction of trifluoromethylated cyclic-sulfoximines has been developed via [3 + 2] cycloaddition reaction of benzynes and trifluoromethyl alpha,beta-unsaturated N-(S)-tert-butyl sulfinylketoimines. The reaction affords the cyclosulfoximines at room temperature in low to moderate yields (13%similar to 57%) and KF as fluorinated reagent, 18-C-6 as additives, and acetonitrile and toluene as mixed solvent (V:V=4:1). The insecticidal activities against Aphis gossypii were determined by impregnation method. The results showed that 24-h median lethal concentrations (24 h LC50) of (1R,3S)-1-(tert-butyl)-3-((E)-4-methylstyryl)-3-(trifluoromethyl)-3H-1 lambda(4)-benzo-[d]isothiazole 1-oxide) (3b) and (1R,3S)-1-(tert-butyl)-3-(trifluoromethyl)-3-((E)-4-(trifluoromethyl)styryl)-3H-1 lambda(4)-benzo[d]isothiazole 1-oxide (3h) are lower than that of the positive control imidacolprid (0.0800 mg/L) and dinitraz (0.0532 mg/L). They can be used as new lead insecticidal compounds with further structure modification.

Automated summary

A concise and direct synthetic strategy for the construction of trifluoromethylated cyclic-sulfoximines has been developed through a [3 + 2] cycloaddition reaction. The reaction yields cyclosulfoximines in low to moderate yields at room temperature using KF as a fluorinated reagent, 18-C-6 as additives, and acetonitrile and toluene as a mixed solvent. The synthesized compounds exhibit lower insecticidal activities against Aphis gossypii.