Exceptionally bulky, oxygenophilic methylaluminumbis(4-bromo-2,6-di-tert-butylphenoxide) (reagent A) can be utilized as an active catalyst for the transformation of various epoxides to carbonylcompounds with high efficiency and selectivity.
Palladium-catalysed oxidation of alcohols with carbon tetrachloride, formation of 4,4,4-trichloro ketones from allylic alcohols and carbon tetrachlorid
作者:Hideo nagashima、Koji Sato、Jiro Tsuii
DOI:10.1016/s0040-4020(01)91368-7
日期:1985.1
Pd salts catalyseoxidation of alcohols with CCl4 in the presence of K2CO3. Primary alcohols are oxidised to esters, and secondaryalcohols to ketones. CCl4 is converted to CHCl3. The reaction of allylicalcohols bearing a terminal olefinic bond with CCl4 or BrCCl3 in the presence of palladium catalyst at 110° affords 4,4,4-trichloro ketones. At 40°, simple adducts of CCl4 or BrCCl3 having a halohydrin
An effective procedure for the synthesis of acid-sensitive epoxides: Use of 1-methylimidazole as the additive on methyltrioxorhenium-catalyzed epoxidation of alkenes with hydrogen peroxide
作者:Shigekazu Yamazaki
DOI:10.1039/b926575a
日期:——
An effective method for suppression of ring opening and rearrangement of acid-sensitive epoxides during methyltrioxorhenium(MTO)-catalyzed epoxidation of alkenes with H2O2 by using 1-methylimidazole as a co-additive has been found. The combined use of 3-methylpyrazole and 1-methylimidazole as the additives has been found to be an effective procedure that affords excellent yields of acid-sensitive epoxides for MTO-catalyzed epoxidation.
Production of Piperonal, Vanillin, and <i>p</i>-Anisaldehyde via Solventless Supported Iodobenzene Diacetate Oxidation of Isosafrol, Isoeugenol, and Anethol Under Microwave Irradiation
作者:Heiddy Marquez Alvarez、Dayse P. Barbosa、Alini Tinoco Fricks、Donato A. G. Aranda、Ricardo H. Valdés、O. A. C. Antunes
DOI:10.1021/op060117t
日期:2006.9.1
is possible to generate the corresponding aldehydes in reasonable-to-excellent yields and selectivities. The methodology is simple, clean, and reproducible and presents short reaction times. Using isosafrol, isoeugenol, and anethol it was possible to produce piperonal, vanillin and p-anisaldehyde, respectively.
The immobilized organoaluminum columns can be successfully utilized as a workup-free reactor for the catalytic rearrangement of various epoxides to carbonyl compounds.