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1611047 
Journal Article 
Structure-reactivity relationship for alcohol oxidations via hydride transfer to a carbocationic oxidizing agent 
Lu, Yun; Bradshaw, J; Zhao, Yu; Kuester, W; Kabotso, D 
2011 
Yes 
Journal of Physical Organic Chemistry
ISSN: 0894-3230 
24 
12 
1172-1178 
WOS:000297934600007 
Second-order rate constants were determined for the
oxidation of 27 alcohols ((RRCHOH)-R-1-C-2) by a carbocationic oxidizing agent, 9-
phenylxanthylium ion, in acetontrile at 60 degrees C. Alcohols include open-chain alkyl,
cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol
were determined at three H/D positions of the alcohol (KIE alpha-D = 3.9, KIE beta-D3 = 1.03,
KIEOD = 1.10). These KIE results are consistent with those we previously reported for the 2-
propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer
mechanism that involves a rate-limiting formation of the a-hydroxy carbocation intermediate.
Structure-reactivity relationship for alcohol oxidations was deeply discussed on the basis of the
observed structural effects on the formation of the carbocationic transition state (C delta+-OH).
Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric
hindrance effect and ring strain relief effect win over the electronic effect in determining the
rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl
alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl
alcohols. Strained C-7-C-11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the
strained C-5 and C-12 alcohols react slower. Aromatic alcohols would be efficiently and
selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements.
This structure-reactivity relationship for alcohol oxidations via hydride-transfer mechanism is
hoped to provide a useful guidance for the selective oxidation of certain alcohol functional
groups in organic synthesis. Copyright (C) 2011 John Wiley & Sons, Ltd. Supporting information
may be found in the online version of this article. 
alcohol oxidations; alpha-hydroxy carbocation; hydride-transfer; structure-reactivity relationship