Productdistributions resulting from the OH-induced oxidation of but-1-ene, 2-methylbut-1-ene, 3-methylbut-1-ene and isoprene in air were measured in the absence of nitrogen oxides and compared with predictions based on currently accepted oxidation mechanisms. In the case of butenes, the observed distributions of carbonyl compounds, hydroxyketones, hydroxyalkanals and diols were evaluated to obtain
Synthesis of enantiomerically pure α-hydroxyaldehydes from the corresponding α-hydroxycarboxylic acids: novel substrates for Escherichia coli transketolase
作者:Andrew J. Humphrey、Nicholas J. Turner、Raymond McCague、Stephen J. C. Taylor
DOI:10.1039/c39950002475
日期:——
Enantiomerically pure (R)-α-hydroxyaldehydes (>95% ee) are prepared from the corresponding α-hydroxyesters by silyl protection, reduction with diisobutylaluminium hydride, and finally deprotection under acidic conditions; subsequent coupling of these aldehydes with lithium hydroxypyruvate, catalysed by Escherichia coli transketolase, leads to novel optically pure triols.
A Novel Approach to γ-Hydroxy-α,β-unsaturated
Compounds
作者:Henryk Krawczyk、Katarzyna Wąsek、Jacek Kędzia
DOI:10.1055/s-0028-1083162
日期:——
A simple synthesis of (E)-alk-1-enyl mesylates from (E)-alk-1-enylphosphonates is reported. Construction of γ-hydroxy-α,β-unsaturated compounds was achieved by a two-step process involving dihydroxylation of the enol mesylates followed by HWE reaction of the resulting α-hydroxy aldehydes with activated methylphosphonates. Enantioselective synthesis of the title compounds is also reported.
Kinetics of oxidation of pantothenic acid by chloramine-T in perchloric acid and in alkaline medium catalyzed by OsO4: A mechanistic approach
作者:Puttaswamy、R. V. Jagadeesh
DOI:10.1002/kin.20068
日期:2005.4
Kinetics of oxidation of pantothenicacid (PA) by sodium N-chloro-p-toluenesulfonamide or chloramine-T (CAT) in the presence of HClO4 and NaOH (catalyzed by OsO4) has been investigated at 313 K. The stoichiometry and oxidation products are same in both media; however, their kinetic patterns were found to be different. In acidmedium, the rate shows first-order dependence on [CAT]o, fractional-order
Influence of α-methyl substitution of proline-based organocatalysts on the asymmetric α-oxidation of aldehydes
作者:Sok-Teng (Amy) Tong、Margaret A. Brimble、David Barker
DOI:10.1016/j.tet.2009.04.060
日期:2009.6
The direct asymmetric organocatalytic α-oxidation of aldehydesusing trans-2-(p-methylphenylsulfonyl)-3-phenyloxaziridine is reported. This method affords the S isomer of α-hydroxy aldehydes, thereby complementing the selectivity for the R isomer observed using the two-step nitrosobenzene method. Use of α-methylproline and α-methylproline tetrazole significantly increases the enantioselectivity observed