| Abstract
| - An efficient method for the construction of two carbon−carbon bonds in a regio- and stereoselectivefashion via palladium-catalyzed assembling of allenes, organic halides, and arylboronic acids isdescribed. Organic halides (RI = C6H5I, o-, m-, and p-CH3OC6H4I, p-C2H5OCOC6H4I, p-CH3COC6H4I,p-CH3C6H4I, p-CH3C6H4Br, p-CH3C6H4Cl, p-NO2C6H4I, p-NO2C6H4Br, p-NO2C6H4Cl, p-IC6H4Cl,1-iodonaphthalene, 2-iodothiophene, 3-iodo-2-cyclopenten-1-one, 3-iodo-5,5-dimethyl-2-cyclohexen-1-one, C6Η5(Br)CCH2 and ICH2CO2C2H5), and arylboronic acids (ArB(OH)2, Ar = C6H5, p-CH3OC6H4, m-NO2C6H4, p-FC6H4, 1-C10H7, and o-, m-, and p-CHOC6H4) undergo Suzuki-type three-component assembling with 1,1-dimethylallene to give the corresponding allylic derivatives,(CH3)2CRCH2Ar, in DMF at 70 °C in the presence of CsF using Pd(dba)2 as the catalyst. Higheryields of products were obtained for aryl iodides than for the corresponding aryl bromides andchlorides. This three-component assembling is highly regioselective, with the organic group onhalides adding to the middle carbon and the aryl group on arylboronic acids to the unsubstitutedterminal carbon of allenes. Monosubstituted allenes 1b−e (cyclopentylallene, cyclohexylallene, tert-butylallene, and n-butylallene) also undergo similar assembling reaction with organic halides andarylboronic acids to afford the corresponding products 7a−i with high regio- and stereoselectivity.Based on the known palladium chemistry, a mechanism is proposed to account for the catalyticreaction and the stereochemistry.
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