8-3 Halohydrins from Alkenes Halohydrin Formation (electrophilic addition) Reaction of alkenes with hypohalous acids HO-CI or HO-Br to yield 1,2-halo alcohols called halohydrins HX ho An alkene A halohydrin In marine organisms halohydrin formation is carried out by haloperoxidases that oxidize Br or Cl ions to corresponding HOBr or HOCI bonded to a metal atom in the enzyme for subsequent addition to the double bond of substrate H OH CH2OH H202.Br,pH=3 CH2OH Bromoperoxidase Halohydrin Formation (electrophilic addition) ▪ Reaction of alkenes with hypohalous acids HO-Cl or HO-Br to yield 1,2-halo alcohols called halohydrins ▪ In marine organisms halohydrin formation is carried out by haloperoxidases that oxidize Br- or Cl￾ions to corresponding HOBr or HOCl bonded to a metal atom in the enzyme for subsequent addition to the double bond of substrate 8-3 Halohydrins from Alkenes