1 / 5

CH 8-1 Electrophilic Addition of HX

Chapter 8: Electrophilic Addition of an Electrophile (E+) and Nucleophile to Alkenes. CH 8-1 Electrophilic Addition of HX

pfierros
Download Presentation

CH 8-1 Electrophilic Addition of HX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 8: Electrophilic Addition of an Electrophile (E+) and Nucleophile to Alkenes CH 8-1 Electrophilic Addition of HX (1) Electrophilic Addition of HX (HCl & HBr) -What is an “electrophile”? -Carbocation mechanism (rearrangements possible) -Regioselective: “Markovnikov’s Rule” -Non-stereospecific reaction (2) Electrophilic Addition of H2O and ROH -Acid catalyzed -Carbocation mechanism (rearrangements possible) (3) Electrophilic Addition of Br2 and Cl2 -”Halonium ion” mechanism -No carbocation -Stereospecific reaction

  2. Electrophilic Addition of an Electrophile (E+) and Nucleophile to Alkenes • Electrophile (E+): an electron deficient atom (“Lewis Acid”) • E+ must have a d+ or full positive charge • E+ is always paired with a nucleophile (Nuc) • Alkene sp2 carbons labeled d- (least substituted) and d+ (most substituted) • Regioselective Reaction (Markovnikov Addition): • E+ is attracted to the d- carbon (pi electrons “grab” E+) • Nuc is attracted to and “grabs” the d+ carbon

  3. Electrophilic Addition of an Electrophile (E+) and Nucleophile to Alkenes (1) Electrophilic Addition of HX (HCl & HBr) -Carbocation mechanism -Regioselective: “Markovnikov’s Rule” -Non-stereospecific reaction -Rearrangements possible (2) Electrophilic Addition of H2O and ROH -Acid catalysis -Carbocation mechanism -Rearrangements possible (3) Electrophilic Addition of Br2 and Cl2 to alkenes -”Halonium ion” mechanism -No carbocation -Stereospecific reaction

  4. Electrophilic Addition of an Electrophile (E+) and Nucleophile to Alkenes (1) Electrophilic Addition of HX (HCl & HBr) -Carbocation mechanism -Regioselective: Markovnikov’s Rule -Non-stereospecific reaction -Rearrangements possible

  5. Electrophilic Addition of HX: non-Stereospecific • The electrophile adds randomly to either side of the double bond, and nucleophile to either side of carbocation: • Random addition produces all possible stereoisomers: in this case a Racemic Mixture of enantiomers (50:50 mix).

More Related