Lipase Ps-C Catalysed Hydrolysis Of Aryl Deesters: A New Route To The Synthesis Of Achiral Half Esters
摘要:
Pseudomonas cepacia lipase supported on ceramic particles (PS-C) offers a simple alternative route for the synthesis of achiral half esters, with very high yields, easy work up and remarkable substrate selectivity, as it cleaves only phenolic esters having a phenyl group (i.e. C6H5-O-CO-C6H5).
HF–Pyridine: A Versatile Promoter for Monoacylation/Sulfonylation of Phenolic Diols and for Direct Conversion of <i>t</i>-Butyldimethylsilyl Ethers to the Corresponding Acetates
Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF–pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF–pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.
is commercially available, is a practical and useful Lewis acidcatalyst for acylation of alcohols with acidanhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acidanhydrides of not only primary alcohols but also sterically-hindered secondary
Bi(OTf)(3)-catalyzed acylation of alcohols with acidanhydride was evaluated in comparison with other acylation methods. The Bi(OTf)(3)/acidanhydride protocol was so powerful that sterically demanding or tertiary alcohols could be acylated smoothly. Less reactive acylation reagents such as benzoic and pivalic anhydride are also activated by this catalysis. In these cases, a new technology was developed
Electrostatic catalysis by ionic aggregates: scope and limitations of Mg(ClO4)2 as acylation catalyst
作者:Asit K Chakraborti、Lalima Sharma、Rajesh Gulhane、Shivani
DOI:10.1016/j.tet.2003.08.007
日期:2003.9
Alkali and alkaline earthmetal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4)2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric
Molybdenum Hexacarbonyl Mediated Alkoxycarbonylation of Aryl Halides
作者:Motoki Yamane、Wei Ren、A. Emi
DOI:10.1055/s-0030-1260060
日期:2011.7
Mo(CO)6-mediates the alkoxycarbonylation of arylhalides in their reaction with alcohols to afford arenecarboxylic acid esters. The molybdenum carbonyl complexes act as the catalyst and the source with carbon monoxide. The alkoxycarbonylation proceeds with a small excess of carbon monoxide in the form of Mo(CO)6 and the procedure is simple compared to the conventional method, which uses palladium catalyst