Insecticidal efficacy of six new pyrrole derivatives against four stored-product pests.

Several pyrrole derivatives exhibit insecticidal activity and can be effective as grain protectants. In the present study, we evaluate the insecticidal efficacy of six novel pyrrole derivatives, namely methyl 3-(methylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1 carboxylate (compound syn) (2a-syn), methyl 3-(methylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound anti) (2a-anti), methyl 3-(benzylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound syn) (2f-syn), methyl 3-(benzylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound anti) (2f-anti), methyl 3-(butylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1-carboxylate (3e), and methyl 2-benzyl-3-(methylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1-carboxylate (0665), against four important species infesting stored products, the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae), the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrychidae), the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae), and the Mediterranean flour moth, Ephestia kuehniella (Lepidoptera: Pyralidae). The six pyrrole derivatives were evaluated on wheat at different doses (0.

Diels-Alder Cycloadditions of Masked o-Benzoquinones with Alkenes.

Diels-Alder cycloadditions of 3-oxobut-1-enyl substituted orthoquinone monoketals with olefinic dienophiles furnished functionalized ortho-endo bicyclo[2.2.2]octenone derivatives with high regio- and stereoselectivities.

Metal-catalyzed thermal reactions of cyclic β-dicarbonyl phenyliodonium ylide with styrenes.

A cyclic β-dicarbonyl phenyliodonium ylide reacted with various substituted styrenes under Rh2(OAc)4 catalysis to give cyclopropanes and dihydrofurans in a highly regioselective fashion. When styrenes with electron-donating substituents or disubstituted were employed, only dihydrofurans were isolated instead. A mechanism involving two competing pathways rationalizes the results.

The question of electrophilic vs nucleophilic addition of cyclic β-dicarbonyl phenyliodonium ylides: electrophilic cycloaddition of diphenylketene.

The reaction of β-dicarbonyl phenyliodonium ylides with diphenylketene at room temperature affords mixtures of lactone and aurone derivatives. The initial electrophilic attack of the iodonium ylide on the C(β) position of the diphenylketene, followed by cyclization of the zwitterionic species, and subsequent ejection of iodobenzene, affords the lactone and aurone cycloadducts. Treatment of β-dicarbonyl iodonium ylides with acyl chlorides yields α-chloroenones with good to excellent yields.

A facile diastereoselective synthesis of functionalized 1,2,3-trisubstituted benzocyclopentenes through the cycloaddition of bis(phenylsulfonyl)iodonium ylides to cyclic alkenes.

The thermal cycloaddition of beta-disulfonyl iodonium ylides to cyclic alkenes affords exclusively 1,2,3-trisubstituted cis(1,2)/cis(2,3)-configured benzocyclopentenes by an electrophilic attack of the ylide on the olefinic double bond. This unsual transformation provides a convenient and direct method for the diastereoselective synthesis of functionalized bicyclo[3.3.

Alkenyl C-H insertion of iodonium ylides into pyrroles: studies toward the total syntheses of tolmetin and amtolmetin guacil.

The thermal-catalyzed or photochemical reaction of iodonium ylides with pyrroles yields exclusively alpha-substituted pyrroles in moderate to good yields. [reaction: see text]