Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• trifluoromethylated isothiazolium thiocyanates and 4-thiocyanato-2,5-dihydrofurans is presented through hydrothiocyanation/cyclization of CF3-iminopropargyl alcohols using NaSCN in AcOH/MeCN. The formation of the two products can be explained by different directions of cyclization of the primary adducts of thiocyanic

• acid at the triple bond – vinyl thiocyanates. This protocol features simple operating, readily prepared starting materials and occurs under relatively mild conditions. Keywords: CF3-alkynyl imines; hydrothiocyanation; isothiazolium thiocyanates; propargyl alcohols; sodium thiocyanate; Introduction

• trifluoromethylated isothiazolium thiocyanates and 4-thiocyano-2,5-dihydrofurans via the reaction of CF₃-iminopropargyl alcohols with NaSCN/AcOH. The tandem process includes hydrothiocyanation of the triple bond followed by cyclization of the intermediates with the participation of the SCN group and an intramolecular