Carbonylation of Alkenes and Dienes

Abstract

In the beginning, only cobalt catalysts were utilized for hydroformylation under relatively vigorous conditions. The moderate selectivity of the generally more desired linear isomers, the substantial formation of by-products, and the low stability of the catalysts forced more appropriate catalytic systems to be developed. Using donor ligands such as phosphanes resulted in an increase in the linear selectivity. Rhodium-containing catalysts, however, permitted the use of much milder conditions in combination with suitable ligands. Other transition metals such as ruthenium, palladium, platinum, and iridium also tended to show activity for hydroformylation, albeit a vast majority of works on hydroformylation still concentrated on rhodium-containing systems. Cobalt CatalystsThe initial rate of Co 2 (CO) 8 -catalyzed cyclohexene hydroformylation, triethyl orthoformate carbonylation, and CoH(CO) 4 formation from Co 2 (CO) 8 and H 2 is reduced by the addition of dinitrogen, argon, or xenon. It is assumed that the additional gas competes with one or more reactants for a coordinatively unsaturated site responsible for their activation, thus affecting the reaction rate [1].The carbonylation reaction of propylene oxide in the presence of various [Lewis acid] þ [Co(CO) 4 ] À salts was investigated using in situ attenuated total reflection infrared (ATR-IR) spectroscopy. b-Alkoxy-acyl-cobalttetracarbonyl species were found to be key intermediates from which two reaction routes start depending on the applied Lewis acid. Labile Lewis acid-alkoxy combinations primarily favor the production of lactone products [2].The reaction of olefins (1-octene, 3,3-dimethylbutene, cyclohexene) introduced into a preequilibrated Co 2 (CO) 8 þ H 2 system was investigated by high-pressure infrared spectroscopy. Based on the observed induction period for the formation of the corresponding aldehyde, the decrease in HCo(CO) 4 concentration and increase in Co 2 (CO) 8 concentration during the induction period, the active catalytic species of the type H x Co y (CO) z was proposed [3]. Experiments with isotope mixtures of H 2 /D 2 in the gas phase during the various steps of the reaction showed that the ratio of H/D isotopes in the hydrocarbon portion of the aldehyde product correlates with the HCo(CO) 4 /DCo(CO) 4 ratio in solution, whereas the RC(¼O)H/RC(¼O)D product ratio correlates with the H 2 /D 2 in the gas phase. It was concluded that the dominant pathway for the hydrogenolysis step in this type of hydroformylation is the direct reaction of hydrogen or deuterium with the acyl complex intermediate [4].The effect of argon (280 bar) on the rate of aldehyde formation in 1-hexene hydroformylation catalyzed by Co 2 (CO) 8 at 50 C, 70 bar P(CO) and 85 bar P(H 2 ) in toluene was investigated by high-pressure FT-IR spectroscopy. The initial rate of the reaction was found to be reduced by the presence of argon. A similar effect was observed in the RhH(CO)(PPh 3 ) 3 -catalyzed cyclohexene hydroformylation reaction [5]. 162j 7 Carbonylation of Alkenes and D...

New Sustainable Pd(II)/Fe(III) Catalytic System Very Efficient in the Hydromethoxycarbonylation of 1-octene

“…The PPh 3 /Pd molar ratio was also found to have a significant role in catalytic activity. The main role of PPh 3 , added to the [Pd(TsO) 2 (PPh 3 ) 2 ] catalyst, is to avoid the formation and the precipitation of inactive Pd metal (see introduction [26,27,41], increasing therefore the catalyst performance. According to this, the Fig.…”

“…Their simple but versatile chemistry is used in applications as diverse as food essence, pharmaceutics, plastics, resins, lubricants, paper, bio-fuel, in cosmetics and the personal care industry [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The industrial production is still mostly based on the Fisher reaction [16][17][18][19][20], but an interesting alternative is represented by the catalyzed hydroalkoxycarbonylation of olefins, a high versatile and atom-efficient reaction [21][22][23][24][25][26][27][28][29][30].…”

Nickel/photoredox-catalyzed carbonylative transformations of α-phosphorus-, α-sulfur-, and α-boron-substituted alkyl halides

“…Carbonylation reactions have become indispensable tools for constructing carbonyl-containing compounds in organic and medicinal chemistry as they enable the efficient and robust union of molecular fragments and carbon monoxide. 3 Over the last few decades, multiple generations of catalytic systems have been explored that have elevated the transition metal-catalyzed carbonylation of organohalides to an essential transformation. 4 Compared with mature noble metal catalysts, cheap metal catalysts such as nickel have also been explored successfully by taking advantage of slow CO-releasing reagents and specialized ligand complexes to minimize the generation of highly toxic and low catalytic activity Ni(CO) n .…”

Iron-Catalyzed Aminoalkylative Carbonylative Cyclization of Alkenes toward α-Tetralones

“…After decades of development, numerous outstanding achievements on carbonylation have been reported, but most of them were focused on Pd, Rh, Ni, Cu, etc . Iron, as an earth-abundant, less toxic, and environmentally friendly metal, has attracted increasing attention in the fields of organic synthesis and catalytic transformations .…”