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ERIC Number: EJ921273
Record Type: Journal
Publication Date: 2010-Dec
Pages: 2
Abstractor: As Provided
Reference Count: 7
ISSN: ISSN-0021-9584
The Variable Transition State in Polar Additions to Pi Bonds
Weiss, Hilton M.
Journal of Chemical Education, v87 n12 p1355-1356 Dec 2010
A vast majority of polar additions of Bronsted acids to alkynes involve a termolecular transition state. With strong acids, considerable positive charge is developed on carbon and Markovnikov addition predominates. In less acidic solutions, however, the reaction is much slower and the transition state more closely resembles the olefinic product. For conjugated alkynes, the lower-energy transition state can retain the conjugated pi system by undergoing addition to the isolated orthogonal pi bond of the alkyne. As a result, anti-Markovnikov products can predominate. (Contains 5 schemes and 1 note.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A