An Improved Procedure for the Synthesis of 4-Oxopimelate-Derived Materials.¹

Abstract

In the course of one of our synthetic projects we required efficient access to 4-ethylenedioxy-2-carbomethoxycyclohexanone 6.^2,4,5 Synthesis of this material has been traditionally accomplished by conversion of 2-furaldehyde 1 to furylacrylic acid 2 via an Organic Synthesis procedure (90%),³ followed by treatment of 2 with methanolic HCI to afford dimethyl 4-oxopimelate 3 in reported yields of 60%⁴ and 80%.⁵ This latter step requires an especially arduous procedure involving removal of the highly corrosive HCl-saturated methanol by distillation; adding benzene, an additional solvent distillation; retreatment of the residue with methanolic sulfuric acid (apparently to reesterify some monoacid produced from the initial HCl treatment⁴), and ultimately a vacuum distillation.