Dabco-Promoted Transition Metals Palladium Or Copper-Catalyzed Coupling Reactions

Transition metals-catalyzed Heck, Suzuki-Miyaura and Sonogashira coupling reactions are some important methods for the formation of carbon-carbon bonds. Recently, many kinds of catalysts and ligands have been developed for these reactions by the synthetic scientists. The contents of this dissertation mainly discussed the use of amines, in particular Dabco, as ligand for the palladium or copper-catalyzed the above-mentioned reactions.1. The combination of Pd(OAc)₂ with Dabco (1,4-diazabicyclo[2,2,2]octane) was observed as an efficient catalytic system for the Heck reaction. In the presence of Pd(OAc)2 and Dabco, a number of ArX (X = I, Br, and Cl) were coupled with olefins efficiently and selectively to afford the corresponding unsymmetric internal olefins in good to excellent yields. Furthermore, the Pd(OAc)2/Dabco-catalyzed Heck reaction provided high TONs up to 1,000,000.2. An efficient catalytic system using CuI/Dabco for the Heck-type reaction was developed. In the presence of 10 mol% of CuI and 20 mol% of Dabco, the coupling of various aromatic iodides with olefins was carried out efficiently and selectively to afford the corresponding internal olefins in moderate to good yields.3. An efficient catalytic system using Cul/Dabco for the Suzuki-Miyaura cross-coupling reaction was observed. In the presence of10 mol% of Cul and 20 mol% of Dabco, the coupling of various aromatic iodides with Arylboronic acid was carried out efficiently to afford the cross-coupling products in good yields. However, 100 mol% of TBAB and 100 mol% of Cul were required for the couplings of aromatic bromides with arylboronic acids resulting in good yields.4. Cul combined with Dabco was found as an inexpensive and highly efficient catalytic system for the Sonogashira cross-coupling reactions of aryl halides with terminal alkynes. In the presence of 10 mol% of Cul and 20 mol% of Dabco, a varety of ArX (X = I, Br, Cl) were coupled with alkynes to afford the corresponding products in moderate to excellent yields.