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Elimination Reactions of Aryl Furylacetates Promoted by R 2 NH in MeCN : Effects of Base Solvent and β‐Aryl Group on the Ketene‐forming Transition State
Author(s) -
Pyun Sang Yong,
Paik Kyu Cheol,
Han Man So,
Kim Byung Tae,
Cho Bong Rae
Publication year - 2017
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.11285
Subject(s) - ketene , chemistry , aryl , medicinal chemistry , base (topology) , kinetics , stereochemistry , transition state , catalysis , organic chemistry , mathematical analysis , alkyl , physics , mathematics , quantum mechanics
Ketene‐forming elimination from C 4 H 3 (O) CH 2 C (O) OC 6 H 3 ‐2‐X‐4‐ NO 2 ( 1 ) promoted by R 2 NH in MeCN has been studied. The reactions produced elimination products and exhibited second‐order kinetics with Brönsted β = 0.51, and |β lg | = 0.47–0.53, indicating that the reaction proceeds by the E2 mechanism via an E2 ‐central transition state. Comparison of β, |β lg |, ΔH ≠ , and ΔS ≠ values for R 2 NH ‐promoted eliminations from ArCH 2 C (O) OC 6 H 3 ‐2‐X‐4‐ NO 2 reveals that the transition‐state structures for Ar = furyl and thienyl are similar and more symmetrical than that for Ar = Ph. This outcome has been attributed to the greater double bond stabilizing ability of the former than that of the latter.