Synthesis of Paullone

Significance

The paullones inhibit three disease-relevant kinases, GSK-3, CDK-1, and CDK-5 as well as mitochondrial malate dehydrogenase. Most of them possess remarkable in vitro antiproliferative activity. The key step in the synthesis depicted is the oxidative annulation of acetanilide (F) with the internal alkyne E catalyzed by a dicationic rhodium(III) complex to give the indole G. Molecular oxygen is the terminal oxidant.