Action of magnesium on polyhaloalkanes and polyhaloalkenes and synthesis of 5, 5-dichloropentaneboronic acid

Abstract

1. The bromides CHCl2(CH2)nCH2Br and CCl2=CH(CH2)nBr, where n=3 and 5, react with magnesium in ether to give ω,ω-dichloroalkyl (alkenyl)magnesium bromides, in yields of 40–50% for n=3, and 10–20% for n=5. The condensation products [CHCl2(CH2)nCH2-]2 and [CCl2=CH(CH2)n-]2 are also formed in 10–30% of the theoretical yields. 2. 5, 5-Dichloropentaneboronic acid, identified as the iminodiethyl ester, was synthesized from the Grignard reagent, obtained from 1, 1-dichloro-5-bromopentane and magnesium. 3. Bromides of the type CHCl2(CH2)nCH2Br and CC12=CH(CH2)nBr, where n=3 and 5, were obtained from the corresponding chlorides by exchange of the chlorine in the CH2Cl group by bromine.