Chemoenzymatic one-pot reaction of noncompatible catalysts: combining enzymatic ester hydrolysis with Cu(<scp>i</scp>)/bipyridine catalyzed oxidation in aqueous medium
作者:Henning Sand、Ralf Weberskirch
DOI:10.1039/c7ra05451c
日期:——
chemoenzymatic one-pot reactions in aqueousmedia remain challenging and are limited today to metal-catalysts that display high activity in aqueousmedia. Here, we report the first combination of two incompatible catalytic systems, a lipase based ester hydrolysis with a water-sensitive Cu/bipyridine catalyzed oxidation reaction, in a one-pot reaction in aqueous medium (PBS buffer). Key to the solution
Phosphomolybdic Acid: Mild and Efficient Catalyst for Acetylation of Alcohols, Phenols, and Amines under Solvent-Free Conditions
作者:Sung Kim、Santosh Kadam
DOI:10.1055/s-2007-1000859
日期:2008.1
simple and efficient catalyst for the acetylation of alcohols, phenols, and amines. Acetylation reactions with aceticanhydride (1.0 equiv) proceed in excellent yield in the presence of a catalytic amount (0.2 mol%) of PMA at ambient temperature within a relatively short reaction time (<10 min). Structurally diverse alcohols, phenols, and amines undergo acetylationunder solvent-free conditions.
Esterification of Tertiary Amides by Alcohols Through C−N Bond Cleavage over CeO
<sub>2</sub>
作者:Takashi Toyao、Md. Nurnobi Rashed、Yoshitsugu Morita、Takashi Kamachi、S. M. A. Hakim Siddiki、Md. A. Ali、A. S. Touchy、Kenichi Kon、Zen Maeno、Kazunari Yoshizawa、Ken‐ichi Shimizu
DOI:10.1002/cctc.201801098
日期:2019.1.9
process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT‐IR and temperatureprogrammeddesorption using probe molecules demonstrate that both acidic and
Thallium(III) Chloride: A Mild
and Efficient Catalyst for Acylation of Alcohols, Phenols
and Thiols, and for Geminal Diacylation of Aldehydes under
Solvent-Free Conditions
作者:Sung Kim、Santosh Kadam
DOI:10.1055/s-0028-1083148
日期:——
simple and efficientcatalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts ofthallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (<20 min). Structurally diverse alcohols, phenols, thiols and
the mesopores, and serve as an efficient heterogeneous catalyst for the synthesis of heterocycle-containing diarylmethanes via Friedel-Crafts-like alkylation of (hetero)arenes by heterobenzyl acetates under mild reaction conditions without requiring any additives or an inert atmosphere. Using this strategy, the gram-scale synthesis of indole-containing diarylmethane 13 has been accomplished in good yield