A synthetic strategy based upon three basic reactions—enzymatic resolution, oxygen–sulfur exchange, reduction—allowed us to carry out an easy and useful synthesis of a series of new 1,4-sulfanylalcohols from aliphatic γ-lactones. Final products have been obtained in good yields with enantiomeric excesses in a 66–91% range.
Stereospecific cyclodehydration of 1,4-sulfanylalcohols to thiolanes: mechanistic insights
作者:Jean-Jacques Filippi、Elisabet Duñach、Xavier Fernandez、Uwe J. Meierhenrich
DOI:10.1016/j.tet.2008.07.088
日期:2008.10
A series of thiolanes were prepared by cyclodehydration of sulfanylalcohols in the presence of catalytic amounts of p-toluenesulfonic acid or by using K10 clay. The sulfur heterocycles were synthesised in good to excellent yields using either a conventional Dean–Stark method or microwave irradiation under solvent-free conditions. The reaction could be performed regio- and stereoselectively and its
Boron trifluoride and indium(III) trifluoromethanesulfonate were found to efficiently catalyse the isomerisation of thionolactones to thiolactones in good yields. When applied to an optically active γ-thionolactone, the isomerisation reaction proceeded with a complete inversion of configuration by using BF3·Et2O.