17537-32-5Relevant articles and documents
Structure-reactivity relationship for alcohol oxidations via hydride transfer to a carbocationic oxidizing agent
Lu, Yun,Bradshaw, Joshua,Zhao, Yu,Kuester, William,Kabotso, Daniel
, p. 1172 - 1178 (2013/01/12)
Second-order rate constants were determined for the oxidation of 27 alcohols (R1R2CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60°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 (KIEα-D=3.9, KIEβ-D3=1.03, KIE OD=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 α-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 (Cδ+-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 C7-C11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C5 and C12 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
Stereospecific oxygen rearrangement in the reduction of optically pure methyl mandelate to phenylethanol isomers
Angelis,Smonou
, p. 488 - 490 (2007/10/03)
The reduction of methyl (S)-(+)-mandelate, 1, produces the expected 2-phenylethanol, 3, and the unexpected optically pure 1-phenylethanol, 6, by a stereospecific oxygen atom metathesis; which occurs through a styrene oxide intermediate, whose concentration varies with solvent polarity.
On the Thermal Cycloisomerization of 1-Vinylnaphthalene to Acenaphthene. A Mechanistic D-Labeling Study
Zimmermann, Gerhard,Ondruschka, Bernd,Nuechter, Matthias,Kopinke, Frank-Dieter,Remmler, Matthias
, p. 415 - 420 (2007/10/02)
Unlabeled 1-vinylnaphthalene (1) as well as positionally D-labeled 1 have been prepared and subjected to gas phase pyrolysis at low partial pressures of the educt compounds in nitrogen.At 700 deg C, 1 rearranges exclusively to acenaphthene (2).Under the conditions applied a significant H-D-exchange in the 1-vinylnaphthalene as well as in the formed acenaphthene takes place.The results obtained in this way and those resulting from pyrolysis in hydrogen (instead of nitrogen) show that despite the very high degree of dilution the high selectivity of cycloisomerization from 1 to 2 is firstly controlled by H-atom driven radical chain processes, in which the cyclization of the 2-naphthylethylradical dominates the reaction course.
