An Improved Synthesis of 2-Diazo-1,3-diketones

Abstract

The sodium hydride/dibenzo-18-crown-6 ether system was found to be an effective base for the synthesis of 1,3-diketones by the Claisen condensation. The use of potassium fluoride (with or without crown ether) as the base in diazo-transfer reactions extends this reaction to the synthesis of hindered diazo diketones. In the case of isomeric 1,3-diketones, the stereoselectivity of the process considerably rises.