Molecular orbital studies on pericyclic reactions of cinnamyl xanthates in β-cyclodextrin cavities

Abstract

The solid β-cyclodextrin (β-CyD) complex of O-cinnamyl S-methyl dithiocarbonates (xanthate, 1a), upon heating at 45°C, underwent asymmetric [3,3]-sigmatropic rearrangement to give the optically S-(1-phenylallyl) S-methyl dithiocarbonate (2a) with 60% ee. Heating the β-CyD complex of 2a at 120°C caused extrusion of COS to give cinnamyl methyl sulfide (3a) in high yield. The reaction behavior and role of β-CyD are discussed based on molecular orbital calculation data.