Oxidative Alkoxycarbonylation of Alkynes by Means of Aryl α‐Diimine Palladium(II) Complexes as Catalysts

Abstract

Abstract. The straightforward in situ synthesized Bis-(2,6-diisopropyl)-acenaphthenequinonediimine palladium triflate catalyst was generally employed for both the monoalkoxycarbonylation of terminal alkynes, and the bisalkoxycarbonylation of 1,2-disubstituted alkynes by using mild reaction conditions (P CO = 4 bar, Temp. 20°C). Utilizing low catalyst loading (down to 0.5 mol%), a variety of propiolic esters were synthesized with good to excellent isolated yields. Most importantly the system was very efficient not only with methanol but also with a range of different alcohols, starting from the less hindered benzyl alcohol to the most ones, such as isopropanol and tertbutanol.In addition aromatic and aliphatic 1,2-disubstituted alkynes were converted into maleic acid derivatives, together with acid-catalyzed isomerization reaction, showing modest to good selectivity and excellent combined yields. In particular 3-hexyne showed a satisfactory degree of selectivity for the maleic diesters of methanol, and benzyl alcohol, obtaining the corresponding products with good isolated yields.

Bis‐Alkoxycarbonylation of Acrylic Esters and Amides for the Synthesis of 2‐Alkoxycarbonyl or 2‐Carbamoyl Succinates

“…[8] To our knowledge, only Nozaki et al showed, in the regiocontrolled copolymerization process of methyl acrylate with CO, that it is possible to carbonylate both the α-and the β-positions of acrylic esters, using a phosphineÀ sulfonate palladium catalyst (Scheme 1b). [10] The catalyst was based on the combination of a palladium salt with bis(aryl)acenaphthenequinonediimine (BIAN) or 1,4diaryl-2,3-diazabutadiene ligands. [10] The catalyst was based on the combination of a palladium salt with bis(aryl)acenaphthenequinonediimine (BIAN) or 1,4diaryl-2,3-diazabutadiene ligands.…”

“…[9] Recently, we have developed a very efficient catalytic system able to promote the bisalkoxycarbonylation of terminal alkenes, [4e] 1,2-disubstituted olefins [5a] and internal alkynes. [10] The catalyst was based on the combination of a palladium salt with bis(aryl)acenaphthenequinonediimine (BIAN) or 1,4diaryl-2,3-diazabutadiene ligands. Similar Pd(II) com-plexes bearing aryl α-diimine ligands were also used by us in the copolymerization of styrenes with CO, yielding copolymers with a high degree of tacticity.…”

“…showed, in the regiocontrolled copolymerization process of methyl acrylate with CO, that it is possible to carbonylate both the α‐ and the β‐ positions of acrylic esters, using a phosphine−sulfonate palladium catalyst (Scheme b) . Recently, we have developed a very efficient catalytic system able to promote the bis‐alkoxycarbonylation of terminal alkenes, 1,2‐disubstituted olefins and internal alkynes . The catalyst was based on the combination of a palladium salt with bis(aryl)acenaphthenequinonediimine (BIAN) or 1,4‐diaryl‐2,3‐diazabutadiene ligands.…”

The intriguing methoxycarbonylation of trimethylsilylacetylene in the presence of Drent's catalytic system

“…Furthermore, many variations of the parent reaction are known and practiced, [ 1–6 ] such as oxidative carbonylation approaches leading to the synthesis of propiolate esters or maleic diesters. [ 7,8 ]…”

α‐Diimine–Palladium Complexes Incorporated in Vinylic‐Addition Polynorbornenes: Synthesis and Catalytic Activity

“…Although olefin polymerization has been their most remarkable application, palladium–diimine complexes are also useful catalysts in different C–C cross‐coupling reactions, such as the Heck reaction, Kumada, Negishi, or Stille reactions, and the Suzuki reaction, as well as carbonylation processes …”