Premium
Non‐Concerted Cope Rearrangement
Author(s) -
Roth Wolfgang R.,
Gleiter Rolf,
Paschmann Volker,
Hackler Ulrich E.,
Fritzsche Gerd,
Lange Holger
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199806)1998:6<961::aid-ejoc961>3.0.co;2-b
Subject(s) - chemistry , trapping , cope rearrangement , recombination , concerted reaction , activation barrier , ab initio , ab initio quantum chemistry methods , computational chemistry , interpretation (philosophy) , chemical physics , reaction mechanism , mechanism (biology) , density functional theory , stereochemistry , catalysis , molecule , physics , organic chemistry , ecology , biochemistry , quantum mechanics , biology , computer science , gene , programming language
The observation of practically identical activation parameters for the Cope rearrangement 2 → 6 and its “frustrated” counterpart 1 → 5 indicates a two‐step mechanism for the reaction 2 → 6 . Direct proof of this interpretation comes from trapping experiments, which demonstrate the intermediate formation of the diradicals 5 and 9 . From the temperature and oxygen dependences of the trapping rates, recombination barriers of Δ H ≠ = 11.5 and 6.5 kcal · mol −1 have been derived for 5 → 1 and 9 → 6 , respectively. These results agree well with ab initio calculations (CASPT2).
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom