Easily accessible halohydrin esters as advantageous hydroxyethylation reagents

Halohydrin esters could be versatile synthetic reagents, but their conventional synthesis commonly involved hazardous ethylene oxide. An economic, mild, safe and scalable one-step halohydrin esters synthesis was achieved from easily accessible NaX, concentrated sulfuric acid, and polyol esters. The halohydrin esters products were applied in hydroxyethylation reactions with various nucleophiles in replacement of EO. Repetition of the protocol allowed unsymmetric difunctionalization of diol esters. The mechanism likely involves acyloxonium intermediate through neighboring group participation.