ZLM-chapter 4-reactions of alkenes

ZLM-chapter 4-reactions of alkenes - LMZ/CHEM109A/ Winter...

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LMZ/CHEM109A/ Winter 2010 Chapters 4: Reactions of alkenes I. Electrophilic Addition reactions e.g. H C C H H CH 3 H C C H Br CH 3 H H CC H CH 3 H H HB r + + Br 1st step 2nd step + - H A. Electrophilic addition of H-X to alkenes (sec. 4.1) - Regioselectivity - carbocation stability - Hammond postulate: transition state is more similar in structure to the species to which it is more similar to energy - why the regioselectivity? -- lower activiation energy Bell-Evans-Polani principle: in a series of closely related reactions, E a is proportional to Δ H ° or Δ G °. - Markovnikov’s rule: In the ionic addition of an unsymmetrical reagent to a double bond, the positive portion of the adding reagent attaches itself to a carbon atom of the double bond so as to yield the more stable carbocation as an intermediate. B. Addition of water (Hydration of alkenes and alkynes) and addition of alcohol 1. Acid catalyzed hydration of alkene (Sec. 4.5) a. mechanism :
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LMZ/CHEM109A/ Winter 2010 b . Regiochemistry: Markovnikov’s type H on ______
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This note was uploaded on 03/01/2010 for the course CHEM 109A taught by Professor Bruice during the Spring '07 term at UCSB.

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ZLM-chapter 4-reactions of alkenes - LMZ/CHEM109A/ Winter...

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