Efficient Allylation of Nucleophiles Catalyzed by a Bifunctional Heterogeneous Palladium Complex-Tertiary Amine System

We demonstrate the synergistic catalysis of a silica-supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/NEt2) as well as synthetic scope of the TsujiTrost reaction of 1,3-dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt2 exhibited wide applicability and high activity for the TsujiTrost reaction. For example, the reaction of ethyl 3-oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 degrees C for 5h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0mmol of ethyl 3-oxobutanate using 0.60mol of Pd in SiO2/diamine/Pd/NEt2, the turnover number (TON) of Pd reached up to 1070 within 24h. Phenols with electron-withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p-chlorophenol.