Enantioselective synthesis of spirocyclic tetrahydrothiophene derivatives bearing a benzofuran-3(2H)-one scaffold. Unusual supramolecular crystal structure with high Z′

Herein, we report our studies on the enantioselective synthesis of spirocyclic tetrahydrothiophene derivatives bearing a benzofuran-3(2H)-one scaffold. The developed method utilizes 2-arylidenebenzofuran-3(2H)-ones and 2-thioacetaldehyde, generated in situ from 1,4-dithiane-2,5-diol, as starting materials and proceeds in a cascade manner involving a thio-Michael-aldol reaction sequence. The absolute configuration of the obtained tetrahydrothiophenes was assigned by single crystal X-ray analysis. Unusually high Z' crystal packing was found in the crystal. (C) 2016 Elsevier Ltd. All rights reserved.