Direct Transformation of Propargylic Alcohols and O,O-Diethyl Phosphorothioic Acid into S-(2H-Chromen-4-yl) Phosphorothioates

Abstract

An environmentally benign and efficient method has been successfully developed to generate S-(2H-chromen-4-yl) phosphorothioates from easily available 2-(3-hydroxyprop-1-ynyl)phenols and O,O-diethyl phosphorothioic acid [(EtO)2P(O)SH] with water as the only byproduct. The reaction proceeds smoothly in moderate to excellent yields. It is noted that (EtO)2P(O)SH acts not only as an acid promoter, but also as the nucleophile to attack the allenic carbocation intermediate.