Current time in Korea 01:04 Oct 21 (Sat) Year 2017 KCS KCS Publications
KCS Publications
My Journal Log In Register
HOME > Search > Browsing(BKCS) > Archives

Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 33, Number 9
BKCSDE 33(9)
September 20, 2012 

 
Title
Eliminations from (E)-2,4-Dinitrobenzaldehyde O-Aryloximes Promoted by R3N in MeCN. Effects of β-Aryl Group and Base-Solvent on the Nitrile-Forming Transition-State
Author
Bong Rae Cho, Eun Mi Ryu, Sang Yong Pyun*
Keywords
Elimination, E2 and E1cb-like
Abstract
Nitrile-forming eliminations from (E)-2,4-(NO2)2C6H2CH=NOC6H4-2-X-4-NO2 (1a-e) promoted by R3N in MeCN have been studied kinetically. The reactions are second-order and exhibit Brönsted β = 0.83-1.0 and |βlg| = 0.41-0.46. The results have been interpreted in terms of highly E1cb-like transition state with extensive Cβ- H bond cleavage and limited Nα-OAr bond cleavage. Comparison with existing data reveals that the structure of the transition state changes from E2-central to highly E1cb-like either by the change of the β-aryl group from Ph to 2,4-dinitrophenyl under the same condition or by the base-solvent system variation from EtO−-EtOH to Et3N-MeCN for a given substrate (1a-e).
Page
2976 - 2980
Full Text
PDF / Supporting Information