Reactions of Alkenes and Alkynes: A Summary, Study notes of Organic Chemistry

Download Reactions of Alkenes and Alkynes: A Summary and more Study notes Organic Chemistry in PDF only on Docsity! CEM 143 SUMMER 2009 The following is a reaction summary to help you remember all the reactions that you should know from Chapter 3. ALKENES: The following reactions involve carbocation intermediates. If you have a symmetric alkene/alkyne (same thing attached to both ends of the multiple bond) then it does not matter where you add the first bond. However, if the alkene/alkyne is unsymmetric then you must add the first bond to the position that leaves the most stable carbocation as the intermediate (methyl < primary < secondary < tertiary < allylic) H X HX HX = HCl, HBr, HI, H-OSO3H (H2SO4) Addition of Hydrogen Halides: Acid-catalyzed addition of water: H2SO4 (H +), H2O OH H X X X2 X = Cl, Br or I Addition of Halides: CEM 143 SUMMER 2009 HX HX = HCl, HBr, HI, H-OSO3H (H2SO4) 1,2 & 1,4 Additions to Conjugated Dienes: H2SO4 (H +), H2O X2 X = Cl, Br or I H X H X H OH H OH X X X X ***IF EXCESS REAGENT ADDED TO THE ABOVE ALL DOUBLE BONDS WILL REACT AS SEEN BELOW*** HX (excess) HX = HCl, HBr, HI, H-OSO3H (H2SO4) Additions to NON-Conjugated Dienes: X2 (excess) X = Cl, Br or I H X X H X X X X CEM 143 SUMMER 2009 H X HX (excess) HX = HCl, HBr, HI, H-OSO3H (H2SO4) Addition of Hydrogen Halides: Acid-catalyzed addition of water: X H2SO4 (H +), H2O OH H X = Cl, Br or I Addition of Halides: H O H H X X2 (excess) XH Hydroboration/Oxidation: H BH2 H B H H syn addition here H2O2, NaOH, H2O H OH BH3 H O CEM 143 SUMMER 2009 Hydrogenation: H H HH2/Pt H H syn addition here Pt surface H This reaction will reduce a triple bond to a single...it CANNOT stop. HH2/Lindlar's H H syn addition here Pt surface H This reaction will reduce a triple bond to a double...it CAN stop.