100867-08-1Relevant articles and documents
Polymer-supported triphenylphosphine ditriflate: A novel dehydrating reagent
Elson, Kathryn E.,Jenkins, Ian D.,Loughlin, Wendy A.
, p. 2491 - 2493 (2004)
A new type of polymeric dehydrating reagent, readily prepared by the treatment of polymer-supported triphenylphosphine oxide with triflic anhydride, was found to be effective in a variety of dehydration reactions such as ester and amide formation; the polymer-supported triphenylphosphine oxide was easily recovered and reused several times without the loss of activity.
Static phase transfer catalysis for Williamson reactions: Pickering interfacial catalysis
Zhao, Qianqiang,Zhao, Xiao,Peng, Hui,Liu, Yang,Yang, Lihui,Sun, Jie,Yang, Lei,Shen, Yifeng
, p. 3445 - 3453 (2019/07/10)
Pickering interfacial catalysis (PIC) systems are regarded as an innovative platform for the design of efficient static biphasic catalytic reactions. In this study, a static PIC system with high catalytic activity was constructed for a phase transfer cata
Novel polymer-supported coupling/dehydrating reagents for use in organic synthesis
Fairfull-Smith, Kathryn E.,Jenkins, Ian D.,Longhlin, Wendy A.
, p. 1979 - 1986 (2007/10/03)
Two novel dehydrating reagents 3 and 4, based on a phosphonium anhydride and an oxyphosphonium triflate respectively, were prepared by reaction of the corresponding polymer-supported phosphine oxides with triflic anhydride. Reagent 3, based on the novel phosphorus heterocycle 1,1,3,3-tetraphenyl-2-oxa-1,3- diphospholanium bis(trifluoromethanesulfonate), was found to be a useful reagent for ester and amide formation. A wide range ofcoupling/dehydration-type reactions, such as ester, amide, anhydride, peptide, ether and nitrile formation, were performed in high yield using the more readily prepared polymer-supported triphenylphosphine ditrinate 4, which was easily recovered and re-used several times without loss of efficiency. With primary alcohols, both reagents 3 and 4 provide an alternative to the Mitsunobu reaction, where the use of azodicarboxylates and chromatography to remove the phosphine oxide by-product can be avoided. The use of 4-dimethylaminopyridine allowed the esterification of secondary alcohols with 4 to proceed in high yield but with retention of configuration.
Indium metal as a reducing agent in organic synthesis
Pitts,Harrison,Moody
, p. 955 - 977 (2007/10/03)
The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
The α-Effect in Benzyl Transfers from Benzylphenylmethyl Sulfonium Salts to N-Methylbenzohydroxamate Anions
Fountain,Tad-y, Darlene B.,Paul, Timothy W.,Golynskiy, Mikhail V.
, p. 6547 - 6553 (2007/10/03)
The investigation of the occurrence of the α-effect in group transfers from phenyldialkyl sulfonium ions where one alkyl group is benzyl allows an assay of the effect of changing the nature of the C atom being transferred. The size of the α-effect responds to increasing electron demand, as methyl transfers do. Quantitative relationships between the size of the α-effect are established from both the nucleophilic side and the leaving group side of the SN2 transition state.
