C_sp2–Br bond activation of Br-pyridine by neophylpalladacycle: formation of binuclear seven-membered palladacycle and bipyridine species

Abstract

A small library of seven-membered palladacycles and asymmetric bipyridines was prepared via C–Br activation and C–C coupling reactions.

Synthesis ofN-alkenylisoquinolinonesviapalladium-catalyzed cyclization/C4–O bond cleavage of oxazolidines

“…This method enriches the diversity of bipyridine derivatives, which are common ligands in organometallic chemistry. 17 In addition, the palladium-catalyzed cross-coupling of cyclic enamide 2a with o -xylene 11 led to the β-arylation product 12 in 39% yield (Scheme 3b). A palladium-catalyzed C–H arylation reaction of 2a with aryl iodide 13 forms the desired product 14 in 69% yield (Scheme 3c).…”

Rollover Cyclopalladation via Remote C‐H Bond Activation of Br‐Pyridinbenzothiazole: An Experimental Study

“…Initially, we heated the reaction mixture at 210 °C for two days, having in mind a potential formation of bipyridine species, according to our earlier report . As a result, yellow pale microcrystals were obtained together with palladium black and an orange solution.…”

Cycloneophylpalladium(IV) Complexes: Formation by Oxidative Addition and Selectivity of Their Reductive Elimination Reactions

“…Previous studies of reductive elimination from cycloneophylpalladium(IV) complexes have shown a high degree of selectivity, though the reactions may occur by C−C coupling to give the cyclobutane derivative CB or by CH 2 −X or Ar−X coupling to give organopalladium(II) products (Schemes 1 and 2). [19][20][21][22][23][24][25][26][27][28][29]50 However, the reductive elimination reactions from the palladium(IV) complexes 3−6 were not very selective (Scheme 6 and Table 1). The decomposition of 3−6 in CDCl 3 solution gave the cyclobutane derivative CB by C−C coupling in yields ranging from 5 to 30% (Table 1).…”

“…It is now well established that Pd­(II)/Pd­(IV) cycles are important in catalysis by palladium complexes, especially in reactions involving strong oxidants such as halogens, dioxygen, and peroxides. , For example, the catalytic reaction of iodine with alkanes or arenes to form iodo-containing hydrocarbons is thought to involve alkane C–H bond activation to form an alkylpalladium­(II) complex, followed by oxidative addition of iodine and then reductive elimination from palladium­(IV). − These impressive advances have stimulated further efforts to understand the factors that affect reactivity and selectivity in oxidative addition at palladium­(II) and reductive elimination from palladium­(IV) complexes. − In studies of selectivity in reductive elimination, the cycloneophylpalladium­(IV) complexes have played an important role as a model to distinguish between reactivity at C­(sp 2 ) or C­(sp 3 ) centers. ,,,,− When the palladium­(IV) complexes ( A ) are sufficiently stable to be isolated, the mechanisms of reductive elimination have been studied and, in most cases, have been shown to involve five-coordinate intermediates such as B (Scheme ). − , External nucleophilic attack on such intermediates occurs selectively at the CH 2 group and can lead, for example, to C–O or C–N bond formation (Scheme a).…”