نتایج جستجو برای: benzoins
تعداد نتایج: 32 فیلتر نتایج به سال:
Cross-coupling of aromatic aldehydes or benzoins with unactivated imines catalyzed by an N-heterocyclic carbene (NHC) affords alpha-amino ketones smoothly.
An efficient, economic and environmentally friendly enantioselective oxidation of racemic benzoins (alpha-hydroxy ketones) catalyzed by a chiral iron complex has been developed using molecular oxygen as a terminal oxidant with good selectivity and excellent enantiomeric excess.
Alumina or silica gel are used as catalysts for a solvent-free oxidation of benzoins to the corresponding benzils. These catalysts are easily recovered after completion of the reactions, which are carried out either by heating in a sand bath or using microwave irradiation. Comparison of the results obtained with both catalysts indicates that all the reactants examined were oxidized faster on al...
[reaction: see text] Benzaldehyde lyase from the Pseudomonas fluorescens catalyzes the reaction of aromatic aldehydes with methoxy and dimethoxy acetaldehyde and furnishes (R)-2-hydroxy-3-methoxy-1-arylpropan-1-one and (R)-2-hydroxy-3,3-dimethoxy-1-arylpropan-1-one in high yields and enantiomeric excess via acyloin linkage. Aromatic aldehydes and benzoins are converted into enamine-carbanion-li...
An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure....
4-chloro-3,5-dioxaphosphacyclohepta[2,1-;3,4-']dinaphthalene (binol-pcl) was found to be an efficient, bulky and selective reagent for the transformation of symmetric and asymmetric benzoins to the corresponding benziles at 0 °c to room temperature under nitrogen atmosphere in good yield.
Oxidation of some benzoins to benziles is reported by using p-toluenesulfonic acid as aselective oxidation catalyst under solvent-free condition in high yield. The adjacent carbonylgroup is necessary for the oxidation of hydroxyl group in these compounds. The reaction iscarried out in a sand-bath at 100 °C with minimum by-products.
4-Chloro-3,5-dioxaphosphacyclohepta[2,1-;3,4-']dinaphthalene (BINOL-PCl) was found to be an efficient, bulky and selective reagent for the transformation of symmetric and asymmetric benzoins to the corresponding benziles at 0 °C to room temperature under nitrogen atmosphere in good yield.
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