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R&D issues for the application of Pd-and Ni-catalyzed C À C and C À N coupling reactions in the fine chemicals industry are discussed. In a first part, some background is given on industrial R&D and the role of C À C and C À N coupling for preparative applications is described. The following principal approaches to industrial research are illustrated with relevant examples from the literature and from our own laboratories: i) development of catalysts and catalytic methodologies with industrial potential; ii) finding shorter routes to target molecules using catalytic methods; iii) development of industrial catalytic processes in multi-step syntheses.

Wichtige Pd‐katalysierte Reaktionen von Arylchloriden verlaufen mit entweder isolierten oder in situ erzeugten Palladiumphosphankomplexen (Beispiel siehe Bild) mit hohen Ausbeuten. Die isolierten Katalysatoren sind an der Luft stabil, und die in situ hergestellten können durch Modifizieren der beiden Ausgangskomponenten optimiert werden.

Primary aromatic amides were prepared by a palladium-catalyzed aminocarbonylation reaction of aryl halides in high yields (70-90%) using formamide as the amine source. The reactions require a palladium catalyst in combination with a nucleophilic Lewis base such as imidazole or 4-(dimethylamino)pyridine (DMAP). Aryl, heteroaryl, and vinyl bromides and chlorides were converted to the primary amides under mild conditions (5 bar, 120 degrees C) using 1 mol % of a palladium-phosphine complex. Best results were obtained in dioxane using triphenylphosphine as the ligand and DMAP as the base. For activated aryl bromides, a phosphine-to-palladium ratio of 2:1 was sufficient, but less reactive aryl bromides or aryl chlorides required ligand-to-palladium ratios up to 8:1 in order to stabilize the catalyst and achieve full conversion. The influence of catalyst, base, solvent, pressure, and temperature was studied in detail. The mechanism of the reaction could be clarified by isolating and identifying the reaction intermediates. In addition, methylamides and dimethylamides were prepared by the same method using N-methylformamide and N,N-dimethylformamide as the amine source.

A series of new rhodium complexes with chiral ferrocenyl chelating ligands containing a tertiary phosphine and a pyrazole moiety have been obtained in good yields from the reaction of the corresponding P,N ligand (1a − p) with [Rh(1,5-COD)2]BF4, [Rh(CO)2Cl]2, and [Rh(COE)2Cl]2. The electronic influence of the P,N ligands has been evaluated by the measurement of the carbonyl stretching vibration in the compounds 5a − p. Qualitative trend correlations between ν(CO) values for such complexes and the enantioselectivities obtained in the Rh-catalyzed hydroboration of styrene utilizing the corresponding ligands have been found. Thus, both electron-donating groups on the pyrazole and electron-withdrawing substituents on the phosphine lead to both higher enantioselectivities and higher CO stretching frequencies. The compounds [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(1,5-COD)]BF4 (3a), [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-bis(trifluoromethyl)-1H-pyrazole}Rh(1,5-COD)]BF4 (3h), [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(CO)Cl] (5k), and [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(CO)Cl] (5n) have been characterized by X-ray diffraction and were found to display very similar conformational features.

A series of new chiral ferrocenyl chelating ligands containing a tertiary phosphine and a pyrazole moiety (3) have been obtained in moderate to good yields from the reaction of the corresponding phosphinoferrocenyl amine derivatives la-k with the V-I-pyrazoles 2a-w in acetic acid at temperatures between 70 and 90 "C. For unsymmetrically substituted pyrazoles a remarkable site selectivity is observed, leading in most cases to only one regioisomer. Six compounds have been characterized by X-ray diffraction and were found to display very similar conformational features.

COMMUNICATIONSwith a Bruker IFS-66 FT-IR spectrometer in the range 4000-400 cm-' with a resolution of I cm-'. Description of the matrix isolation equipment: W Sander, J! Org.