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A radical route in the biomimetic oxidation of a tertiary amine
Author(s) -
Cuppoletti Andrea,
Galli Carlo,
Gentili Patrizia,
Petride Horia
Publication year - 2002
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.533
Subject(s) - chemistry , ring (chemistry) , aziridine , flash photolysis , steric effects , tertiary amine , electron transfer , amine gas treating , photochemistry , radical ion , radical cyclization , imine , medicinal chemistry , radical , reaction rate constant , stereochemistry , organic chemistry , kinetics , catalysis , ion , physics , quantum mechanics
Whereas the biomimetic oxidative N ‐dealkylation of tertiary amines with t ‐BuOOH and an iron(III) tetraphenylporphyrin typically proceeds by an electron transfer (ET) route, a radical H‐atom transfer (HAT) route has been found to operate with N ‐benzylaziridine (1), an amine that is fairly resistant towards one‐electron oxidation for steric reasons. New mechanistic information is presented in favour of this radical route, and the exclusive formation of the dimeric product N , N ′‐dibenzylpiperazine (2) is explained in the light of the Baldwin's rules. Flash photolysis data provide a rate constant of 1.7 × 10 5 s −1 for the ring opening of the aziridine radical (1 . ) to the imine radical (4 . ) in the early stages of the process leading to 2. Semiempirical calculations indicate the ring‐opened radical 4 . to be more stable than 1 . . Copyright © 2002 John Wiley & Sons, Ltd.