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Mechanism of flash vacuum pyrolysis of phenyl propargyl ether. Intramolecular deuterium kinetic isotope effect on claisen rearrangement

Journal Article · · J. Org. Chem.; (United States)
DOI:https://doi.org/10.1021/jo00412a054· OSTI ID:6509342
NMR analyses were performed on the reaction products obtained from the flash vacuum pyrolysis(FVP) of phenyl ..gamma..-deuteropropargyl ether(I) and 2-deuterophenyl propargyl ether(II) to ascertain the reaction mechanism. The FVP was carried out at 460/sup 0/C and 0.02 Torr. The NMR spectrum of undeuterated 2-indanone in carbon tetrachloride displayed peaks at delta 7.15 (singlet, aromatic hydrogen's) and 3.25 (singlet, nonaromatic hydrogen's) and with an integration constant of 1.00 : 1.00, while the NMR spectrum of the deuterated 2-indanone derived from I produced an aromatic protons/nonaromatic protons ratio of 1.30 : 1.00. The NMR analyses of the reaction products from FVP of II indicate that at the rate-determining transition state the oxygen-propargylic (..cap alpha.. carbon) bond is stretched in advance of any significant bond formation between the acetylenic carbon (..gamma.. carbon), the Claisen type rearrangement was classified as a nonsynchronous process and the proposed mechanism agrees with previous studies.
Research Organization:
Univ. of Baghdad
OSTI ID:
6509342
Journal Information:
J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 43:18; ISSN JOCEA
Country of Publication:
United States
Language:
English