936331-31-6Relevant academic research and scientific papers
General and stereoselective aminoxylation of biradical titanium(iv) enolates with TEMPO: A detailed study on the effect of the chiral auxiliary
Kennington, Stuart C. D.,Gómez-Palomino, Alejandro,Salomó, Ernest,Romea, Pedro,Urpí, Fèlix,Font-Bardia, Mercè
, p. 4807 - 4815 (2018/07/13)
A comprehensive analysis of the influence of the chiral auxiliary on the α-aminoxylation of titanium(iv) enolates with TEMPO indicated that (S) 4-tert-butyl-1-oxazolidine-2-thione is the most appropriate scaffold to provide a single diastereomer in high yields for a variety of substrates, which converts such a radical reaction into a highly chemo- and stereoselective oxidation.
Asymmetric α-oxyamination of aldehydes by synergistic catalysis of imidazolethiones and metal salts
Liang, Xianrui,Li, Na,Chen, Xinlei,Su, Weike
, p. 44039 - 44042 (2014/12/11)
Novel and efficient imidazolethione catalysts combined with metal salts were successfully introduced to the asymmetric α-oxyamination of aldehydes. The desired products with high yields and good to excellent enantioselectivities were obtained via a one-pot oxidation-oxyamination reaction system.
Stereoselective aminoxylation of biradical titanium enolates with TEMPO
Gomez-Palomino, Alejandro,Pellicena, Miquel,Romo, Juan Manuel,Sola, Ricard,Romea, Pedro,Urpi, Felix,Font-Bardia, Merce
, p. 10153 - 10159 (2014/08/18)
A highly efficient and straightforward aminoxylation of titanium(IV) enolates from (S)-N-acyl-4-benzyl-5,5-dimethyl-1,3-oxazolidin-2-ones with TEMPO has been developed. A wide array of functional groups on the acyl moiety, including alkyl and aryl substituents, olefins, esters, or α-cyclopropyl, as well as α-trifluoromethyl groups, are well tolerated. This transformation can therefore produce the α-aminoxylated adducts in excellent yields with high diastereomeric ratios (d.r.). In turn, parallel additions to the α,β-unsaturated N-acyl counterparts give the corresponding γ-adducts with complete regioselectivity in moderate to good yields. Removal of the piperidinyl moiety or the chiral auxiliary converts the resultant adducts into enantiomerically pure α-hydroxy carboxyl derivatives, alcohols, or esters in high yields under mild conditions. Finally, a new mechanistic model based on the biradical character of the titanium(IV) enolates has been proposed.
Peptide/laccase cocatalyzed asymmetric α-oxyamination of aldehydes
Akagawa, Kengo,Kudo, Kazuaki
, p. 3498 - 3501 (2011/09/14)
An asymmetric α-oxyamination could be successfully performed by a peptide catalyst and laccase. The combination of peptide catalysis and enzymatic air oxidation promoted the reaction smoothly in water without employing a metal reagent. The oxyaminated compounds could be obtained as both aldehyde and carboxylic acid products depending on the reaction conditions.
One-pot sequential alcohol oxidation and asymmetric α-oxyamination in aqueous media using recyclable resin-supported peptide catalyst
Akagawa, Kengo,Fujiwara, Takuma,Sakamoto, Seiji,Kudo, Kazuaki
scheme or table, p. 8040 - 8042 (2011/01/03)
An efficient tandem reaction system was developed, in which primary alcohols were used for the oxidation to the corresponding aldehydes followed by an asymmetric α-oxyamination with a resin-supported peptide catalyst.
Efficient asymmetric α-oxyamination of aldehydes by resin-supported peptide catalyst in aqueous media
Akagawa, Kengo,Fujiwara, Takuma,Sakamoto, Seiji,Kudo, Kazuaki
supporting information; experimental part, p. 1804 - 1807 (2010/09/06)
The resin-supported peptide catalyst having the terminal five-residue Pro-d-Pro-Aib-Trp-Trp combined with polyleucine successfully catalyzed the asymmetric α-oxyamination of aldehydes in aqueous media. The secondary structure and the chirality sense of th
