Electron Spin Resonance Studies in Aqueous Solution: Fragmentation of Radical Intermediates Derived from β-Amino Alcohols

Authors:
  • TFTerry Foster
    Terry Foster
  • PWPaul Ronald West
    Paul Ronald West
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Abstract
In acidic aqueous solution, oxidation of the β-amino alcohols [ ], I, and [ ], II, (R = H, alkyl) using the Ti(III)–H2O2 flow technique gave the radicals [ ], and [ ]. The spectrum of [ ] shows restricted rotation about the C1—C2 bond assigned to intramolecular hydrogen bonding.Under neutral conditions, oxidation of I gave the spectrum of •CH2CHO, and of II the acetonyl radical •CH2COCH3. It is proposed that elimination occurs by deprotonation of the abstraction radical in a hydrogen-bonded conformation, followed by rapid fragmentation to yield the α-carbonyl radical.