β-KETO ESTERS FROM REACTION OF ETHYL DIAZOACETATE WITH KETONES

Abstract

The Lewis acid catalyzed reaction of diazoacetic ester with ketones has been extended. Convenient conditions have been found for the preparation of some pure β-keto esters in fair to good yields by reaction of ethyl diazoacetate with ketones in the presence of boron trifluoride at −40° to −70°. The reaction is apparently general since cyclopentanone, cyclohexanone, and acetophenone gave nearly pure β-keto esters in 44%, 79%, and 38% yields, respectively, based on diazoacetic ester. In the case of acetophenone the phenyl group migrated. Acetone gave 78% of a mixture of β-keto ester and glycidic ester.