Nonactivated phenols have been employed as nucleophiles in the allylation of nonderivatized allylic alcohols to generate allylated phenolic ethers with water as the only byproduct. A Pd[BiPhePhos] catalyst was found to be reactive to give the O-allylated phenols in good to excellent yields in the presence of molecular sieves. The reactions are chemoselective in which the kinetically favored O-allylated products are formed exclusively over the thermodynamically favored C-allylated products.
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http://dx.doi.org/10.1021/acs.joc.7b03274 | DOI Listing |
J Chromatogr A
February 2021
Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, PR China. Electronic address:
Comprehensive analysis of fatty acids (FAs) has long been challenging due to their poor ionization efficiency, lack of characteristic fragment ions and difficulty of identifying C=C bond locations. In this study, a high coverage ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for the quantification and C=C bond location characterization of FAs using two structural analogues, 2-hydrazinyl-4,6-dimethylpyrimidine (DMP) and 2-hydrazinylpyrimidine (DP), as dual derivatization reagents. DP-labeled FA standards were used as internal standards to reduced matrix effects, which guaranteed the accurate quantification of FAs.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2019
Department of Organic Chemistry, Stockholm University, Arrheniuslaboratorierna, 10691, Stockholm, Sweden.
The stereospecific substitution of non-derivatized and non-allylic enantioenriched alcohols with only water as a by-product would enable the use of readily available alcohols as substrates for green and sustainable transformations. However, the poor leaving group ability of the OH group has hampered the development of such a process. Denton and co-workers recently described the use of (2-hydroxybenzyl)diphenylphosphine oxide as a catalyst of a redox-neutral and zero-waste-generating Mitsunobu reaction.
View Article and Find Full Text PDFJ Org Chem
April 2018
Department of Organic Chemistry , Stockholm University, 106 91 , Stockholm , Sweden.
Nonactivated phenols have been employed as nucleophiles in the allylation of nonderivatized allylic alcohols to generate allylated phenolic ethers with water as the only byproduct. A Pd[BiPhePhos] catalyst was found to be reactive to give the O-allylated phenols in good to excellent yields in the presence of molecular sieves. The reactions are chemoselective in which the kinetically favored O-allylated products are formed exclusively over the thermodynamically favored C-allylated products.
View Article and Find Full Text PDFChemistry
March 2018
Department of Organic Chemistry, Stockholm University, 106 91, Stockholm, Sweden.
Palladium-catalyzed allylic substitution of non-derivatized enantioenriched allylic alcohols with a variety of uncharged N-, S-, C- and O-centered nucleophiles using a bidentate BiPhePhos ligand is described. A remarkable effect of the counter ion (X) of the XPd[κ -BiPhePhos][η -C H ] was observed. When ClPd[κ -BiPhePhos][η -C H ] (complex I) was used as catalyst, non-reproducible results were obtained.
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