Thionyl chloride - A versatile reagent

Abstract

(A) Thionyl chloride is a powerful chlorinating reagent. It reacts with most carbonyl or aromatic sulfoacid compounds to give carboxylic acids or aromatic sulfochlorides, respectively.3,4 (Chemical Equation Presented) (B) A monochloroxime steroid reacts with thionyl chloride in the presence of pyridine traces in benzene via an abnormal Beckmann rearrangement.5 (Chemical Equation Presented) (C) Chlorination of amino alcohols with thionyl chloride gives chloroethyl amides; if excess thionyl chloride is used, the reaction yields chloroethyl imidoyl chlorides. 6 (Chemical Equation Presented) (D) Ortho-diols react with thionyl chloride to give sulfites (a mixture of two diastereomers) in excellent combined yields.7 (Chemical Equation Presented) (E) In the presence of a Lewis acid catalyst, 2-methylanisole reacts with SOCl2 in a Friedel-Crafts reaction, which yields the corresponding aryl sulfinyl chloride.8 (Chemical Equation Presented) (F) Thionyl chloride can also be used as a chlorinating agent through its oxidation and partial dehydrogenation of organic compounds.9 (Chemical Equation Presented) (G) Thionyl chloride is also used as a cyclization reagent to synthesize heterocyclic compounds.10,11 (Chemical Equation Presented) (H) Thionyl chloride can be used as an HCl precursor and reacts with compounds containing C-C multiple bonds.12 (Chemical Equation Presented) (I) (1R,6S)-7-oxabicyclo[4.1.0]heptane was regioselectively ring-opened under supramolecular catalysis conditions to afford (1S,2S)-2-chlorocyclohexanol. 13 (Chemical Equation Presented) (J) Thionyl chloride also serves as condensing agent.14 (Chemical Equation Presented). © Georg Thieme Verlag Stuttgart.