Selenium and Tellurium Tetrachlorides as Reagents for the Conversion of Alcohols to Alkyl Chlorides and Tellurium Tetrachloride as a Lewis Acid Catalyst for Aromatic Alkylation

Abstract

Selenium tetrachloride(SeCl4) reacts smoothly with alcohols in various nonpolar solvents to give the corresponding alkyl chlorides in 44–97% yield. Similar reaction also proceeds with tellurium tetrachloride (TeCl4), while the treatment of benzyl, 1-phenylethyl, and t-butyl alcohols with TeCl4 in aromatic solvents results in a high yield formation of alkylated aromatics instead of alkyl chlorides. Such Friedel-Crafts aromatic alkylation hardly occurs in the SeCl4 case. The chlorinating species is not chlorine which might be evolved by dissociation of SeCl4 or TeCl4, but the metal chloride itself. The conversion of optically active (R)-(+)-1-phenylethanol to 1-phenylethyl chloride proceeds with nearly complete racemization.