スズ-ヘテロ原子結合に基づく有機スズの新反応

抄録

Reagents containing carbon-tin-halogen inter-element linkages were found to be effective for palladium-catalyzed cross-coupling reaction with organic halides. It also enabled carbostannylation of norbornenes. Tetraorganotins were found to become quite efficient reagents for palladium-catalyzed cross-coupling reaction with organic halides, providing up to all four organic moieties on tin for the reaction upon addition of fluoride ion. Hydroxide ion was even more effective in utilizing plural number of organic groups on tin atom. In situ generated allylic tin trichlorides add to carbon-carbon double bonds of bicyclo [2.2.1] hept-2-ene (norbornene) and its derivatives, stereoselectively, under the catalysis of palladium (0) species in good yields. Aryltin trichlorides undergo palladium-catalyzed arylstannylation of norbornene, giving a mixture of products composed of that taking one norbornene and that incorporating two norbornenes. The product ratio is dependent on the electronic nature of the aromatic substituent. The reaction of vinyltin trichlorides is different, giving Heck-type product that does not contain tin moiety. The mechanistic study revealed that tin (IV) species oxidatively reacted with norbornene.