Hydroxycarbonylation of aryl halides with formate salts catalyzed by palladium complexes

Palladium/Rhodium Cooperative Catalysis for the Production of Aryl Aldehydes and Their Deuterated Analogues Using the Water–Gas Shift Reaction

“…[2] In view of the multiple steps involved and the associated production of large quantities of waste,r esearch efforts have been directed towards finding superior routes.T he reductive carbonylation of aryl halides using CO as acarbonyl source has emerged in the last decade as am ore atom-economic and less wasteful alternative. [3] In the reductive carbonylation approach, phosphineligated Pd catalysts are employed to form the Pd aroyl species through oxidative addition into the aryl-halogen bond followed by migratory insertion of CO.T oprovide the formyl hydrogen atom and complete the catalytic cycle,e xternal reductants have been applied including tin hydrides, [4] metal formates, [5] hydrogen, [3] and, more recently,s ilanes [6] and water with stoichiometric amounts of iron carbonyl [7] (Scheme 1a-d). While these methods are successful in producing non-hindered aryl aldehydes,t he synthesis of hindered aryl aldehydes by reductive carbonylation remains ac hallenge because of the competition from the more rapid reductive dehalogenation pathway.A ttempts to overcome this problem by evaluating different ligands,p erforming the reaction with slow addition of the tin hydride,o rt esting different silanes were not very successful.…”

Synthesis of 4H‐Benzo[e][1,3]oxazin‐4‐ones by a Carbonylation–Cyclization Domino Reaction of ortho‐Halophenols and Cyanamide

“…To further broaden the generality of the reaction we decided to develop a viable procedure for reacting ortho ‐bromophenols. There are few examples in the literature of carbonylative coupling reactions of ortho ‐bromophenols, and these reactions often require harsh conditions and suffer from low yields . There are, however, reports of palladium‐catalyzed aminocarbonylations of electron‐rich aryl bromides using monodentate and bidentate phosphine ligands, for example, di(1‐adamantyl)‐ n ‐butylphosphine (cataCXium A), 1,1′‐bis(diphenylphosphino)ferrocene (dppf), and bis[(2‐diphenylphosphino)phenyl] ether (DPEphos) .…”

An industrially usable Pd-catalyzed carboalkoxylation of 1,2-dibromo-3,3,3-trifluoropropane to tert-butyl trifluoromethacrylate in the presence of an inorganic base

“…Therefore, the result of run 4 clearly proves that HBr and/or H + were scarcely removed from 1 and/or tert-butyl alcohol by Li 2 CO 3 , and that the inorganic bases in Table 1 behave in a different manner from triethylamine. The reaction mechanism of the carboalkoxylation is considered to proceed as follows [8]: (i) HBr abstraction from 1 by triethylamine generates 2-bromo-3,3,3-trifluoropropene (BTP), (ii) oxidative addition of BTP to a palladium species produces a vinyl palladium intermediate A, (iii) CO insertion into the palladium-carbon bond of A forms an acylpalladium species B, and (iv) nucleophilic attack of an alcohol to the carbonyl group of B gives an alkyl trifluoromethacrylate (Scheme 1). Li and Yamamoto proposed that the last step takes place via an intermediate where an acyl, a bromido and an alkoxo ligands coordinate to the palladium [8b].…”