Abstract
Several new palladium-catalyzed addition reactions of allenes and their applications in organic synthesis are described. This thesis consists of two parts. The first part is concerned with new methodology to generate 1,3-butadiene derivatives and the three-component coupling reactions of nucleophilic substitution of p-allylpalladium complexes. The second part deals with the studies on the carbonyl allylation via apparent charge reversal of p-allylpalladium intermediate. In the first part, a palladium-catalyzed reaction based on carbopalladation of allenes to generate a p-allylpalladium intermediate followed by deportonation of the resulting p-allylpalladium species was carried out to transfer allenes into substituted 1,3-butadienes. In addition to the synthesis of 1,3-butadienes, the p-allylpalladium species reacted with carboxylate and azide anions leading to the formation of allylic carboxylates and allylic azides, respectively. In the second part, highly regio- and stereoselective allylation of aldehydes by allenes proceeds smoothly in aqueous/organic media in the presence of PdCl2(PPh3)2, HCl(aq), and SnCl2. The reaction occurs via hydrostannylation of allenes and allylation of aldehydes by the in situ generated allyltrichlorotins to afford the homoallylic alcohols. In addition, the allylation of carbonyl compounds by allylic alcohols via the formation and the apparent charge reversal of the p-allylpalladium complex in the catalytic system, 5 mol % PdCl2(PPh3)2, 10 mol % SnCl2, and excess Zn as metal reducing agent, gave the corresponding homoallylic alcohols.