Selective Aryl alpha-Diimine/Palladium-Catalyzed Bis-Alkoxy- carbonylation of Olefins for the Synthesis of Substituted Succinic Diesters

Aryl alpha-diimine derivatives have been used, for the first time, as efficient new ligands for the palladium-catalyzed oxidative bis-alkoxycarbonylation reaction of olefins. The most active catalyst was formed in situ from bis(9-anthryl)-2,3-dimethyl-1,4-diazabutadiene and palladium(II) trifluoroacetate [Pd(TFA)2]. This catalytic system was able to selectively convert olefins into succinic diesters in good yields (up to 97%) and low catalyst loading (up to 0.5 mol%) under mild reaction conditions [4 bar of carbon monoxide (CO) at 20 °C in the presence of p-toluenesulphonic acid as additive and p-benzoquinone as oxidant]. The optimized conditions could be successfully applied to both aromatic and aliphatic olefins, by using methanol, benzyl alcohol or isopropyl alcohol