Synthesis, structure and catalytic application of palladium(II) complexes bearing N-heterocyclic carbenes and phosphines

Highly efficient N‐Heterocyclic carbene–palladium complex‐catalyzed multicomponent carbonylative Suzuki reaction: novel practical synthesis of unsymmetric aryl ketones

“…Fortunately, as shown in Table 1, the work showed that sodium tetraphenylborate was an efficient phenylating reagent with different catalytic NHC-Pd complexes. The NHC-Pd complex 1-catalyzed 17 carbonylative Suzuki reaction of sodium tetraphenylborate with iodobenzene showed better catalytic activity than complexes 2 and 3. The base was critical for the selectivity of the reaction.…”

Mechanisms of the Mizoroki–Heck Reaction

“…Such a dissociation of the phosphine must be even easier than the intramolecular dissociation of the phosphine in the bidentate P ∧ Cb ligand proposed above. This is probably why mixed complexes Pd 0 (Cb)(PR 3 ) are more efficient than Pd 0 (Cb) 2 in Mizoroki-Heck reactions performed from aryl bromides [71,76], even if they are less reactive than Pd 0 (Cb) 2 in the oxidative addition. Indeed, the high stability of the Cb-Pd(II) bond combined with the easy dissociation of the phosphine in ArPdX(Cb)(PR 3 ) favours the complexation/insertion of the alkene.…”

NHC–Pd(II) complex–Cu(I) co‐catalyzed homocoupling reaction of terminal alkynes

“…33 The palladium-catalyzed terminal alkyne dimerization, through oxidative homocoupling, is a useful approach to the synthesis of symmetrical 1,4-diynes. Reported protocols for the oxidative homocoupling reactions include: (1) use of Pd(PPh 3 ) 4 , CuI, Et 3 N and chloroacetone (as the reoxidant) in benzene; 34 (2) 38 In all of the above cases, a stoichiometric amount of oxidant is required for successful homocoupling reactions. Owing to the inertness of the NHC-Pd(II) complexes towards oxygen and moisture, they have been used as catalysts in aerobic oxidation of alcoholes 33,39 and aerobic intramolecular Wacker-type cyclization reactions.…”