Conversion of Alcohols to Alkyl Halides with SOCI2 and PBr

12 Conversion of Alcohols to Alkyl Halides with SOCI2 and PBrs 

Primary (1 ) and 2° alcohols can be converted to alkyl halides using SOCI2 and PBts. 

Both reagents convert OH into a good leaving group in situ— Ihat is, directly in the reaction mixture—as well as provide the nucleophile, either Cl or Br, to displace the leaving group. 

The treatment of a 1° or 2° alcohol with thionyl chloride, SOCI2, and pyridine forms an alkyl chloride, with SO2 and HCI as by-products. 

The mechanism for this reaction consists of two parts conversion of the OH group into a better leaving group, and nucleophilic attack by Cl via an reaction, as shown in Mechanism 9.7. 

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