Lecture 12 - Nucleophilic Participation During Electrophilic Addition to Alkenes: Halogen, Carbene, and Borane

author: J. Michael McBride, Department of Chemistry, Yale University
recorded by: Yale University
published: Aug. 19, 2014,   recorded: February 2011,   views: 1579
released under terms of: Creative Commons Attribution No Derivatives (CC-BY-ND)
Categories

See Also:

Download Video - generic video source Download yalespan125bs2011_mcbride_lec12_01.mp4 (Video - generic video source 549.9 MB)

Download Video Download yalespan125bs2011_mcbride_lec12_01_640x360_h264.mp4 (Video 146.9 MB)

Download subtitles Download subtitles: TT/XML, RT, SRT


Help icon Streaming Video Help

Related Open Educational Resources

Related content

Report a problem or upload files

If you have found a problem with this lecture or would like to send us extra material, articles, exercises, etc., please use our ticket system to describe your request and upload the data.
Enter your e-mail into the 'Cc' field, and we will keep you updated with your request's status.
Lecture popularity: You need to login to cast your vote.
  Bibliography

Description

When electrophilic addition involves a localized carbocation intermediate, skeletal rearrangement sometimes occurs, but it can be avoided when both alkene carbons are involved in an unsymmetrical 3-center-2-electron bond, as in Markovnikov hydration via alkoxymercuration followed by reduction. Similarly a reagent that attacks both alkene carbons simultaneously by providing a nucleophilic component during electrophilic attack can avoid rearrangement, as in reactions that proceed via three-membered-ring halonium intermediates. Simultaneity in making two bonds during formation of cyclopropanes from carbenes can be demonstrated using stereochemistry. Anti-Markovnikov hydration can be achieved via hydroboration followed by oxidation with hydroperoxide. Rearrangement of the borane hydroperoxide intermediate with frontside C-O bond formation shows close orbital analogy to backside attack during SN2 substitution. Again syn-addition shows that nucleophilic attack occurs simultaneously with electrophilic attack on the alkene.

Link this page

Would you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !

Write your own review or comment:

make sure you have javascript enabled or clear this field: