One-Pot Synthesis of β-Ketoesters from Aryl Methyl Ketone via Ketene Dithioacetal

We have discovered base-mediated conversion of 3,3-bis(methylthio)-1-arylprop-2-en-1-ones to versatile active methylene compounds (beta-keto esters). A series of products were isolated and characterized as a mixture of keto-enol form. We have modified the method and synthesized the active methylene compounds (beta-keto esters) directly from aryl methyl ketone via ketene dithioacetal intermediate (not isolated) by stepwise reactions in one pot. Most of the one-pot reactions also provided excellent yields. In addition to aryl methyl ketones, we also tested cyclopropyl methyl ketone as a source of an aliphatic ketone, and under similar reaction conditions, ethyl 3-cyclopropyl-3-oxopropanoate was afforded.

Automated summary

We have discovered a base-mediated method for the conversion of 3,3-bis(methylthio)-1-arylprop-2-en-1-ones to versatile active methylene compounds (beta-keto esters). By modifying the method, we achieved the synthesis of the target compounds directly from aryl methyl ketone with excellent yields. Cyclopropyl methyl ketone was also tested as a source of aliphatic ketone, yielding the desired product under similar reaction conditions.