Palladium-catalyzed carbonylation reactions of aromatic halides in the presence of various nucleophiles have undergone rapid development since the pioneering work of Heck and co-workers in 1974, such that nowadays a plethora of palladium catalysts are available for different carbonylative transformations. The carboxylic acid derivatives, aldehydes, and ketones prepared in this way are important intermediates in the manufacture of dyes, pharmaceuticals, agrochemicals, and other industrial products. In this Review, the recent academic developments in this area and the first industrial processes are summarized.

Palladium-catalyzed carbonylation reactions of aryl halides and related compounds.

Reactions of hydrosilanes with transition metal complexes and characterization of the products.

Um eine CO-Gruppe reicher: (Hetero-)Arene sind aus der industriellen Herstellung von Agrochemikalien, Farbstoffen, Pharmaka etc. nicht wegzudenken. Wahrend der vergangenen Jahrzehnte wurden ubergangsmetallkatalysierte Kupplungen von Arylhalogeniden mit Nucleophilen aller Art entwickelt. Dieser Aufsatz fasst aktuelle Fortschritte auf dem Gebiet der palladiumkatalysierten Carbonylierungen von Arylhalogeniden und ahnlichen Verbindungen zusammen (siehe Schema).

Palladiumkatalysierte Carbonylierungen von Arylhalogeniden in Gegenwart verschiedener Nucleophile haben sich seit ihrer Einfuhrung durch Heck und Mitarbeiter im Jahr 1974 schnell weiterentwickelt, sodass heute eine Vielzahl von Palladiumkatalysatoren fur unterschiedliche Carbonylierungsreaktionen verfugbar ist. Auf diesem Weg erhaltliche Carbonsaurederivate, Aldehyde und Ketone sind wichtige Zwischenstufen bei der industriellen Herstellung von Farbstoffen, Pharmaka, Agrochemikalien und anderen Produkten. In diesem Aufsatz werden aktuelle Ergebnisse aus der akademischen Forschung und erste industrielle Prozesse zusammengefasst.

Palladiumkatalysierte Carbonylierungen von Arylhalogeniden und ähnlichen Substraten

The time-dependent density functional theory (TDDFT) method was carried out to investigate the hydrogen-bonded intramolecular charge-transfer (ICT) excited state of 4-dimethylaminobenzonitrile (DMABN) in methanol (MeOH) solvent. We demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O formed between DMABN and MeOH can induce the C[triple bond]N stretching mode shift to the blue in both the ground state and the twisted intramolecular charge-transfer (TICT) state of DMABN. Therefore, the two components at 2091 and 2109 cm(-1) observed in the time-resolved infrared (TRIR) absorption spectra of DMABN in MeOH solvent were reassigned in this work. The hydrogen-bonded TICT state should correspond to the blue-side component at 2109 cm(-1), whereas not the red-side component at 2091 cm(-1) designated in the previous study. It was also demonstrated that the intermolecular hydrogen bond C[triple bond]N...H-O is significantly strengthened in the TICT state. The intermolecular hydrogen bond strengthening in the TICT state can facilitate the deactivation of the excited state via internal conversion (IC), and thus account for the fluorescence quenching of DMABN in protic solvents. Furthermore, the dynamic equilibrium of these electronically excited states is explained by the hydrogen bond strengthening in the TICT state.

Time-dependent density functional theory study on hydrogen-bonded intramolecular charge-transfer excited state of 4-dimethylamino-benzonitrile in methanol.

The diamides and disulfonamides m-C6H4(CONHAr)2 (Ar = Ph, 1; p-n-BuC6H4, 2, 2,4,6-Me3C6H2, 3), m-C6H4(SO2NHPh)2, 4, and 2,6-C6H3N(CONHPh)2, 5, readily synthesized on a multigram scale, bind strongly to halides and acetate in organic solvents with Ka's as high as 6.1 × 104 (NMR spectroscopy). The binding stoichiometry is 1:1 in solution for all cases except for the 4·F- and 4·OAc- complexes, where both 1:1 and 1:2 binding stoichiometries were found. The association constants in CD2Cl2 (1H NMR) follow the trend Cl- > Br- > I- for all the receptors. F- and OAc- binding may be stronger or weaker than Cl- depending on the nature of the receptor. The presence of the pyridine nitrogen in 5 and of the more rigid amide in 1−3 and 5 vs the less rigid sulfonamide structure in 4 increases selectivity for smaller anions. The enthalpy and entropy of formation for 2·Cl- were ΔH = −31 kJ/mol; ΔS = −23 J/(mol·K) (VT-NMR). The X-ray structure of [PPh4]2[1·Br][Br]·CH2Cl2, shows 1:1 complexation of Br- via two N−H···Br- hydr...

Hydrogen Bonding in Anion Recognition: A Family of Versatile, Nonpreorganized Neutral and Acyclic Receptors.

Synthesis, Structure, and Silylene Exchange Reaction of Base-Stabilized Hydrido(silylene)tungsten Complexes and Rearrangement of Hydrosilyl(pyridine)tungsten Complexes to the Base-Stabilized Hydrido(silylene) Complexes via 1,2-Hydrogen Migration

Reactions of cis-Cp*(CO)2W(MeCN)Me (1) with HSiMe2(CHCR2) (R = H, Me) afford the novel η3-1-silaallyl complexes Cp*(CO)2W(η3-Me2SiCHCR2) [R = H (2), Me (3)] accompanied by liberation of MeCN and CH4 via thermal Si−H bond activation. η3-Coordination and exo conformation of the 1-silaallyl ligand in 3 are shown by X-ray crystal analysis, which reveals the partial double bond character of the Si−C bond (1.800(4) A) in the silaallyl moiety. Complexes 2 and 3 show extremely high reactivity toward MeOH to give the hydrido-(methoxysilyl)alkene complex trans-Cp*(CO)2WH(η2-MeOMe2SiCHCH2) (4) and the four-membered metallacycle (6), respectively.

Novel η3-1-Silaallyl Tungsten Complexes via Si−H Bond Activation of Hydrovinylsilanes: Structure and Reactivity toward Methanol

Reactions of (η5-C5Me4R)(CO)2(MeCN)WMe (R = Me, Et) with HPh2SiC⋮CtBu gave the novel alkynyl-bridged W−Si complexes, (η5-C5Me4R)(CO)2W(μ-η1:η2-C⋮CtBu)(SiPh2) (R = Me, Et), whose alkynyl ligands bridge the tungsten and silicon atoms in an η1:η2-coordination mode. The structures of these complexes were fully characterized, including X-ray crystallography. Treatment of (η5-C5Me5)(CO)2W(μ-η1:η2-C⋮CtBu)(SiPh2) with acetone resulted in acetone insertion into the silicon−alkynyl linkage followed by intramolecular C−H activation of the tBu group to give the chelate-type alkyl−alkene complex,

η1:η2-Alkynyl-Bridged W−Si Complexes: Formation, Structure, and Reaction with Acetone

The geometry and bonding nature of Cp(CO)2W(C⋮CH)(SiH2) (1) and the reaction leading to the formation of 1 from (9) were theoretically investigated with DFT, MP2 to MP4(SDTQ), and CCSD(T) methods, where 9 and 1 were adopted as models of the interesting new complexes reported recently, and Cp*(CO)2W(C⋮CtBu)(SiPh2), respectively. Our computational results clearly indicate that 1 involves neither a pure silacyclopropenyl group nor pure silylene and acetylide groups and that the silylene group strongly interacts with both the W center and the acetylide group. Frontier orbitals of 1 resemble those observed in the formation of silacyclopropene from silylene and acetylene. The frontier orbitals, as well as the geometry, indicate that the (CCH)(SiH2) moiety of 1 can be understood in terms of an interesting intermediate species trapped by the W center in that formation reaction. Complex 1 is easily formed from 9 through Si−C σ-bond activation with moderate activation barriers of 15.3, 18.8, and 15.8 kcal/mol, whic...

Silapropargyl/Silaallenyl and Silylene Acetylide Complexes of [Cp(CO)2W]+. Theoretical Study of Their Interesting Bonding Nature and Formation Reaction

Hiroyuki Sakaba

Papers

Synthesis, Structure, and Silylene Exchange Reaction of Base-Stabilized Hydrido(silylene)tungsten Complexes and Rearrangement of Hydrosilyl(pyridine)tungsten Complexes to the Base-Stabilized Hydrido(silylene) Complexes via 1,2-Hydrogen Migration

Novel η3-1-Silaallyl Tungsten Complexes via Si−H Bond Activation of Hydrovinylsilanes: Structure and Reactivity toward Methanol

η1:η2-Alkynyl-Bridged W−Si Complexes: Formation, Structure, and Reaction with Acetone

Silapropargyl/Silaallenyl and Silylene Acetylide Complexes of [Cp(CO)2W]+. Theoretical Study of Their Interesting Bonding Nature and Formation Reaction

How to Stabilize η3-Silapropargyl/Alkynylsilyl Complex of [CpL2M]+(L = CO, PMe3, or PF3 and M = W or Mo): Theoretical Prediction