Catalytic carbonylation of β-lactones to succinic anhydrides

A well-defined,highly active and selective catalyst for the synthesis of succinic anhydrides from CO and β-lactones is reported. At 200 psi of CO, the catalyst [(N,N′-bis(3,5-di-tert-butylsalicylidene)phenylenediamino)Al(THF)2][Co(CO)4] carbonylates β-propiolactones to succinic anhydrides in high yield. (R)-β-Butyrolactone is carbonylated to (S)-methylsuccinic anhydride with clean inversion of stereochemistry, while cis-2,3-dimethyl-β-propiolactone yields exclusively trans-2,3-dimethylsuccinic anhydride. These data are consistent with a mechanism involving nucleophilic attack by [Co(CO)4]- on the β carbon of the lactone, followed by CO insertion and anhydride formation. Copyright © 2004 American Chemical Society.