137601-34-4Relevant academic research and scientific papers
Erbium(III) chloride: A very active acylation catalyst
Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Oliverio, Manuela,Procopio, Antonio,Russo, Beatrice,Tocci, Amedeo
, p. 75 - 79 (2008/02/10)
Erbium(iii) chloride is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides (Ac 2O, (EtCO)2O, (PriCO)2O, (Bu tCO)2O, and (CF3CO)2), without isomerization of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity. CSIRO 2007.
Nucleophilic acyl substitutions of anhydrides with protic nucleophiles catalyzed by amphoteric, oxomolybdenum species
Chen, Chien-Tien,Kuo, Jen-Huang,Pawar, Vijay D.,Munot, Yogesh S.,Weng, Shieu-Shien,Ku, Cheng-Hsiu,Liu, Cheng-Yuan
, p. 1188 - 1197 (2007/10/03)
(Chemical Equation Presented) Among six different group VIb oxometallic species examined, dioxomolybdenum dichloride and oxomolybdenum tetrachloride were the most efficient catalysts to facilitate nucleophilic acyl substitution (NAS) of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. In contrast to the well-recognized redox chemical behaviors associated with oxomolybdenum(VI) species, the catalytic NAS was unprecedented and tolerates virtually all kinds of functional groups. By using benzoic anhydride as a mediator for in situ generation of an incipient mixed anhydride-MoO2Cl2 adduct with a given functional alkanoic acid, one can achieve oleate, dipeptide, diphenylmethyl, N-Fmoc-α-amino, pyruvic, and tert-butylthio ester, N-tert-butylamide, and trityl methacrylate syntheses with appropriate protic nucleophiles. The amphoteric character of the Mo=O unit in oxomolybdenum chlorides was found to be responsible for the catalytic NAS profile as supported by a control NAS reaction of using an authentic adduct-MoOCl2(O2-CBu t)2 between pivalic anhydride and MoO2Cl 2 as the catalyst.
Erbium(III) triflate as an extremely active acylation catalyst
Procopio, Antonio,Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Russo, Beatrice,Sindona, Giovanni
, p. 1465 - 1470 (2007/10/03)
Erbium(III) triflate is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides {Ac 2O, (EtCO)2O, [(CH3)3CO] 2O, Bz2O, and (CF3CO)2O} without isomerisation of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.
N-acylpyridinium trifluoromethanesulfonates and tetrafluoroborates: Shuttle reagents for the acylation of enantiopure secondary alcohols
Wagner, Rüdiger,Günther, Wolfgang,Anders, Ernst
, p. 883 - 888 (2007/10/03)
Several enanflopure alcohols are esterified with N-acyl-4- benzylpyfidinium trifluoromethanesulfonates 7b,d,f or tetrafluoroborates 7a,c,e. These reagents, which can be generated in situ, or isolated as stable salts, are synthesized from readily available 4-alkylpyridines 3, acyl chlorides 4 and strong protic acids 6. The acyl moiety is transferred under neutral conditions and in high yields. The heterocyclic component 3a can be re-isolated almost quantitatively. The acetate, benzoate and pivaloate groups were selected with regard to their application as frequently used protecting groups for hydroxy compounds. As shown by paramagnetic shift experiments with a chiral europium(III) complex, these acylations proceed without detectable racemization or epimerization.
An Extremely Powerful Acylation Reaction of Alcohols with Acid Anhydrides Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
Procopiou, Panayiotis A.,Baugh, Simon P.D.,Flack, Stephen S.,Inglis, Graham G.A.
, p. 2342 - 2347 (2007/10/03)
Trimethylsilyl trifluoromethanesulfonate is an excellent catalyst for the acylation of alcohols with acid anhydrides. Highly functionalized primary, secondary, tertiary, and allylic alcohols, and phenols, were acylated cleanly and efficiently and in a fraction of the time used under the standard DMAP conditions.
Scandium trifluoromethanesulfonate as an extremely active Lewis acid catalyst in acylation of alcohols with acid anhydrides and mixed anhydrides
Ishihara, Kazuaki,Kubota, Manabu,Kurihara, Hideki,Yamamoto, Hisashi
, p. 4560 - 4567 (2007/10/03)
Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides 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 acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of ω-hydroxy carboxylic acids.
Improved preparation of angelate esters
Hartmann, Benoit,Kanazawa, Alice M.,Depres, Jean-Pierre,Greene, Andrew E.
, p. 5077 - 5080 (2007/10/02)
A new procedure has been developed for the efficient preparation of angelate esters from alcohols. The alcohol is treated in dry toluene at 70-80°C for 19-36 h with a mixed anhydride prepared from angelic acid and 2,4,6-trichlorobenzoyl chloride. In the absence of base, no tiglate ester is produced.
