A catalytic variant of the direct thiolation of arenes, bearing directing groups, with disulfides or thiols has been developed under palladium and copper co-catalysis. Both sulfenyl moieties of the disulfide could be incorporated into the thiolated products, therefore, the reactions reached completion with only half an equivalent of disulfide, with respect to the starting arene. Experimental evidence suggested that the reaction proceeds through a Pd(II)/Pd(IV) mechanism.
Nickel-catalyzed direct selenation of benzamides bearing an 8-quinolyl auxiliary with elemental selenium provides benzoisoselenazolones in good yield via carbon-selenium and nitrogen-selenium bond formation under aerobic conditions. In addition to aryl C-H bonds, the method can also be applied to alkenyl C-H bonds, constructing an isoselenazolone skeleton. Simple mechanistic analysis shows that the reaction proceeds through a rate-determining C-H bond cleavage. The obtained benzoisoselenazolones are transformed into various organoselenium compounds and utilized as the catalyst for bromolactonization of alkenoic acids.
A palladium-catalyzed and picolinamide-directed C-H thiolation of naphthylamine derivatives with diaryl disulfides has been developed to provide a convenient route to 8-sulfenyl-1-naphthylamines. The reaction proceeds via a 5-membered palladacycle intermediates to afford the peri-thiolated products exclusively, in contrast to the conventional ortho-functionalization. Moreover, the related direct selenation was also achieved with diaryl diselenides, giving the corresponding selenated products with perfect site-selectivity.
A direct selenation of inert C-H bonds of benzamide derivatives and their related compounds with diselenides has been achieved with the palladium catalyst. The reaction was compatible with a variety of functional groups, including a bromo group. Primitive mechanistic insights revealed that the reaction proceeded through a C-H bond cleavage and the sequential oxidative addition of diselenides. The present synthetic method can be applied to the facile synthesis of selenoxanthone which can be regarded as promising heterocyclic materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.