A Regio- and Stereo-Selective Synthesis of a Monoter-Pene-α-Methylene-γ-Butyrolactone

Abstract

In our synthetic work on the transformation of simple p-menthane monoterpenes, readily available from Brazilian essential oils, into biologically active sesquiterpene lactones, we have prepared the model lactone 4 from p-menth-8-ene 1.¹ The key step in this sequence is a lead tetra-acetate (LTA) oxidative cyclisation² of the 1,3 diol 2 into the tetrahydrofuran 3. The final product is the cis fused lactone 4, isolated as two epimers about the methyl group.