Halohydrins X X2 H20 HX HO An alkene A halohydrin C2004 Thomson-Brooks/Cole
Halohydrins
Bromohydrin Formation Addition of Br-OH Stereospecific Regiospecific 6+ nH,0 BrBr Br: bromonium ion H20 Br 9 OH
Bromohydrin Formation Addition of Br – OH Stereospecific & Regiospecific bromonium ion Br Br Br2 + Br Br H2O in H 2O Br OH H Br OH Br -
Unsymmetrical Bromonium ion H2O opens ring at more hindered site Br CH: HO H H H20
Unsymmetrical Bromonium ion H2O opens ring at more hindered site Br CH3 H + + H2 O CH Br 3 HO H
OH N-Br (NBS) CH-CH2 CH一CH2一Br H2O/CH3SOCH3 (DMSO) Styrene 2-Bromo-1-phenylethanol(76%) C2004 Thomson-Brooks/Cole
Br and oH are trans in anti addition Br Br2 in H2O OH CH3
Br and OH are trans in anti addition CH3 Br2 in H 2 O CH3 OH Br