- You can recognize a reaction as an addition reaction based on the conversion of an alkene pi bond to two new bonds, one from each carbon, to a new atom or group.
- You recognize that in catalytic hydrogenation, the two atoms of H2 are delivered to the same face of the alkene: a syn addition.
- You can recognize how a chiral environment is needed (such as a chiral catalyst) in order to achieve enantioselective hydrogenation of an alkene.
- You can identify how an electrophile will interact with a pi bond in an alkene to generate a carbocation.
- If the electrophile is H+ (obviously, delivered by an appropriate conjugate base), you can predict which carbon of the alkene will accept the proton. You understand this as the mechanistic basis for the Markownikov rule.
- For H-X (H = Cl, Br, I, OH) you can predict the result of addition to any alkene.
- You recognize that carbocation rearrangements in H-X additions will behave as they do in E1 eliminations because of the involvement and properties of a carbocation.
- You can generalize the H-X addition mechanism to other species with polar or polarizable bonds: Cl-Cl, Br-Br, I-I, HOCl, HOBr, BrCl, ICl, BrCN, RS-Cl, HgX2/H2O.
Visualization: Bromination of an alkene vs. an alkane (YouTube)
- You understand the participation of lone pairs in forming halonium ions, and the impact on stereospecificity when using X+ as an electrophile.
- You can apply the principles of electrophilic addition to the addition of B-H bonds to alkenes, and understand why we observe anti-Markownikov addition with these reagents.
- You understand the mechanism by which alkylboranes are converted to alcohols by hydrogen peroxide.
- You can use retrosynthetic thinking to see how to make either of two alcohols from an alkene, either by oxymercuration/demercuration, or by hydroboration/oxidation.
- You know that carbenes share electrophilic and nucleophilic character and can add to alkenes to form cyclopropanes. You understand the stereospecific outcome of these additions, based on alkene configuration.
- You know that peroxycarboxylic acids have the same shared electrophilic/nucleophilic character, and can add a single oxygen atom to an alkene to form an epoxide.
- You know that metal oxo reagents OsO4 and KMnO4 will react with an alkene in a syn fashion to form a 1,2-diol (a vicinal diol).
- You know that ozone (O3) will oxidatively cleave alkenes to give carbonyl compounds, and what structural features and elements of the workup lead to ketones, aldehydes or carboxylic acids.
- You understand radical addition to alkenes: in general, the formation of the more substituted alkyl radical, and specifically the formation of anti-Markownikov products in the addition of H-X or formation of polymers.
Recommended end-of-chapter problems: 12-39, 12-40, 12-41, 12-42, 12-44, 12-46, 12-47, 12-48, 12-49, 12-50, 12-53, 12-61, 12-67, 12-78.
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