Formation mechanism of furfuryl sulfides from O-furfuryl dithiocarbonates: Density functional theory study for aromatic [3,3]-sigmatropic rearrangement

Abstract

Density functional theory (DFT) calculations at the B3LYP/6-31G(d) and B3LYP/6-31G+(d) levels demonstrated that O-furfuryl S-alkyl dithiocarbonate (1) undergoes aromatic [3,3]-sigmatropic rearrangement to the energetically unfavorable S-(2-methylene-2,3-dihydrofuran-3-yl) S-alkyl dithiocarbonate (2′), which then rearranges to furfuryl alkyl sulfide (3) with COS extrusion to regain the aromaticity lost in the first step. © 2011 Pharmaceutical Society of Japan.