An operationally simple approach to (E)-α-halo vinyl sulfides and their applications for accessing stereodefined trisubstituted alkenesElectronic supplementary information (ESI) available: Spectroscopic data of products 3, 5, and 7. CCDC 902936. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3ob27307e

An operationally simple and practical protocol for the synthesis of ( E )-α-halo vinyl sulfides has been achieved via a highly regio- and stereoselective hydrohalogenation of alkynyl thioethers using lithium halides in HOAc or propionic acid at room temperature. It permits the formation of ( E )-α-chloro and ( E )-α-bromo vinyl sulfides in satisfactory yields with good to excellent stereoselectivities. Moreover, this work results in a new method for the assembly of stereodefined ( E )- or ( Z )-trisubstituted alkenes featuring the first coupling of the C-X bond of ( E )-α-halo vinyl sulfides followed by a subsequent Ni-catalyzed coupling of the C-S bond with Grignard reagents. Described herein is an operationally simple approach to ( E )-α-halo vinyl sulfides by a regio- and stereoselective hydrohalogenation of alkynyl thioethers, which enables a new entry to stereodefined trisubstituted alkenes featuring the stepwise cross-coupling reactions.