Carbonylation Of Aryl Halides Research Articles

Carbonylation of aryl halides and vinyl bromides mediated by tetracarbonylcobalt anion

The reaction of aryl halides (1a–g) with octacarbonyldicobalt in the presence of methyl iodide and sodium hydroxide under phase-transfer conditions was found to give a mixture of aryl methyl ketones (2a–g) and aromatic carboxylic acids (3a–h). From vinyl halides (9a–c), however, the corresponding carboxylic acids (10a–c) were obtained exclusively.

Nickel-catalyzed amidation of bromo- and iodobenzene

The carbonylation of aryl halides in the presence of p-RC 6H 4NH 2 (R = H, CH 3, Cl) or C 6H 5NHR (R = CH 3, C 6H 5) and a catalytic amount of a nickel(II) or nickel(0) tertiary phosphine complex at 150°C or above under carbon monoxide pressures is reported. Amides were obtained in high yields in reactions with p-RC 6H 4NH 2, but with C 6H 5NHR compounds the expected N-alkyl benzanilides were not formed, benzanilide in low yield being formed instead. A possible catalytic cycle based on an active Ni o-carbonyl complex is suggested, and the observed deactivation of the catalytic system when the carbon monoxide pressure falls to 6 atm or below, is accounted for in terms of a side reaction which produces an inactive Ni II compound.

Activation of reducing agents. Sodium hydride containing complex reducing agents : XIV. NaCoCO 4 as an SRN1 nucleophile in the carbonylation of aryl halides by CoCRACO at atmospheric pressure. New preparation of NaCoCO 4 by NaH reduction of dicobalt octacarbonyl

The only detectable cobalt carbonyl species present in CoCRACO (NaH/t-AmONa/Co(OAc) 2/CO) (t-Am = tert-amyl) is NaCoCO 4. The simultaneous presence of NaH, t-AmONa, NaCoCO 4 and some soluble, non-carbonyl, cobalt species allows highly catalytic carbonylation of C 6H 5Br under very mild conditions, while NaCoCO 4 alone can carbonylate C 6H 5Br under irradiation (350 nm). In the presence of t-AmONa, the reaction is highly catalytic with respect to cobalt. These results strongly suggest a S RN1 mechanism. It is suggested that catalytic carbonylations with CoCRACO take place by a S RN1, electron-initiated, reaction. A new, very convenient method of preparation of NaCoCO 4 by quantitative reduction of Co 2CO 8 with NaH is also described.

ChemInform Abstract: SUBSTITUENT EFFECTS UPON DISSOCIATION AND MIGRATION REACTIONS OF FIVE‐COORDINATE PLATINUM(II) CARBONYL COMPLEXES

AbstractDie durch Addition von Aryliodid an Tetrakis‐ [triphenylphosphin]‐Pt(O) dargestellten Iodoaryl‐Pt(II)‐Komplexe (Ia) bilden bei der Carbonylierung die Acy1‐Pt(II)‐Analogen (IIa).