4743-91-3Relevant academic research and scientific papers
Copper-catalyzed oxytrifluoromethylation of unactivated alkenes
Zhu, Rong,Buchwald, Stephen L.
, p. 12462 - 12465 (2012)
A mild, versatile, and convenient method for the efficient oxytrifluoromethylation of unactivated alkenes based on a copper-catalyzed oxidative difunctionalization strategy has been developed. This methodology provides access to a variety of classes of sy
Asymmetric Aza-Diels-Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N-H Ketimines Catalyzed by Chiral Phosphoric Acids
He, Shunlong,Gu, Huanchao,He, Yu-Peng,Yang, Xiaoyu
supporting information, p. 5633 - 5639 (2020/07/14)
A novel asymmetric synthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels-Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing dihydropyridinones with excellent diastereoselectivities and high enantioselectivities. Mechanistic study and control experiments were performed to shed light on the reaction mechanism, in which a configurationally defined β,β-disubstituted α,β-unsaturated N-H ketimine was proposed as the key intermediate.
Organocatalyzed asymmetric 1,4-addition of azlactones to α,β-unsaturated trichloromethyl ketones: Synthesis of α,α-disubstituted α-amino acid derivatives
Zhang, Jinlong,Liu, Xihong,Wu, Chongyang,Zhang, Panpan,Chen, Jianbo,Wang, Rui
supporting information, p. 7104 - 7108 (2015/01/16)
The first asymmetric 1,4-addition of azlactones to α,β-unsaturated trichloromethyl ketones catalyzed by cinchona alkaloid derived bifunctional thiourea catalysts was developed. A series of α,α-disubstituted α-amino acid derivatives bearing a quaternary stereocenter at the α-position were obtained in high yields with excellent diastereo- and enantioselectivities (up to -20:1 dr and 99% ee). In addition, the trichloromethyl moiety in these adducts was identified as a good leaving group.
Polyclonal antibodies: A cheap and efficient tool for screening of enantioselective catalysts
MacOvei, Cristian,Vicennati, Paola,Quinton, Julia,Nevers, Marie-Claire,Volland, Herve,Creminon, Christophe,Taran, Frederic
supporting information; experimental part, p. 4411 - 4413 (2012/05/20)
Enantioselective polyclonal antibodies have been produced and characterized to develop a high-throughput screening method for lipase activity fingerprinting, with a view to the enantioselective hydrolysis of azlactones.
α-Allylation of α-amino acids via 1,5-hydrogen atom transfer
Chowdhry, Muhammad I.,Horton, Peter N.,Hursthouse, Michael B.,Wood, Mark E.
scheme or table, p. 3400 - 3403 (2009/09/05)
A straightforward method for the radical-based α-allylation of proteinogenic α-amino acids is described in which the key step involves 1,5-hydrogen atom transfer from the C-4 position of an oxazolidin-5-one.
Asymmetric synthesis of uncommon α-amino acids by diastereoselective alkylations of a chiral glycine equivalent
Tanaka, Kiyoshi,Ahn, Mija,Watanabe, Yukari,Fuji, Kaoru
, p. 1771 - 1782 (2007/10/03)
For the purpose of practical preparations of a variety of enantiomerically pure uncommon α-amino acids, alkylations of the chiral glycine equivalent 5, which possesses axially chiral binaphthol as an auxiliary, with several electrophiles were investigated. The alkylation proceeded smoothly in satisfactory chemical yield with high diastereo-selectivities to give protected α-amino acid derivatives. The free hydroxyl group of the auxiliary played an important role for the induction of diastereoselectivity. Using (S)-1,1'-binaphthalene-2,2'-diol as a chiral auxiliary, D-α-amino acid derivatives having the unnatural (R)-configuration were predominantly obtained. Some of the alkylated products were converted into free non- proteinogenic D-α-amino acids.
Synthesis of (Optically Active) Sulfur-Containing Trifunctional Amino Acids by Radical Addition to (Optically Active) Unsaturated Amino Acids
Broxterman, Quirinus B.,Kaptein, Bernard,Kamphuis, Johan,Schoemaker, Hans E.
, p. 6286 - 6294 (2007/10/02)
Sulfur-based radicals, generated from R-S-H-type precursors (R = alkyl, acyl) with AIBN, smoothly add to α-allylglycines protected at none, one, or both of the amino acid functions (NH2 and/or CO2H).Sulfur-containing trifunctional amino acids were obtained in good to excellent yields (64-100 percent).The solvent used for the reaction is critical.Optimal results were obtained when both the unsaturated amino acid and RSH dissolve completely in the medium (dioxane/water or methanol/water are good solvent systems).The scope of the reaction includes α-substituted α-allylglycine derivative and derivatives as well as β-substituted β-allyl-β-amino alcohols.In the case of optically active α-allylglycine derivatives, radical addition is accompanied by a small amount of racemization, the amount depending on the type of protection and R-S-H.The products are easily optically enriched by crystallization.Addition of sulfur-based radicals to α-allylglycine is believed to be an example of a general method for synthesizing optically active trifunctional amino acids from unsaturated amino acids.
