Important Concepts12 1.Double Bond Reactivity – exothermic addition reactions leading to saturated products 2.Hydrogenation of Alkenes – immeasurably slow unless a catalyst is used Palladium on carbon, PtO 2, Raney nickel H 2 preferentially added to the least hindered face of the double bond 3.  Bond – attacked by acid and electrophiles If the initial intermediate is a carbocation, the more highly substituted carbocation is formed (Markovnikov’s Rule). If the initial intermediate is cyclic onium ion, nucleophilic ring opening is at the more substituted carbon (control of both regio- and stereochemistry).

Important Concepts12 4.Hydroboration – mechanistically between hydrogenation and electrophilic addition Step 1:  complexation to boron Step 2: concerted transfer of hydrogen to carbon Hydroboration-oxidation: anti-Markovnikov hydration of alkenes 5.Carbenes and Carbenoids – useful for synthesis of cyclopropanes from alkenes 6.Peroxycarboxylic Acids – contains oxygen atom transferable to alkenes to give oxacyclopropanes (epoxidation) 7.Osmium Tetroxide – addition to alkenes in a concerted syn manner to give vicinal diols

Important Concepts12 8.Ozonolysis – when followed by reduction, yields carbonyl compounds by cleavage of the double bond 9.Radical Chain Additions To Alkenes – Chain carrier adds to the  bond to form the more highly substituted radical Allows for anti-Markovnikov hydrobromination of alkenes Allows for the addition of thiols and some halomethanes 10.Polymers – Alkenes react with themselves to form polymers. Initiation by charged species, radicals or some transition metals