1239488-11-9Relevant academic research and scientific papers
Proline dipeptides containing fluorine moieties as oganocatalysts for the asymmetric aldol reaction
Ahmetlli, Ardiol,Spiliopoulou, Nikoleta,Magi-Oikonomopoulou, Angeliki,Gerokonstantis, Dimitrios-Triantaffylos,Moutevelis-Minakakis, Panagiota,Kokotos, Christoforos G.
, p. 5987 - 5995 (2018)
A series of dipeptide analogues consisting of proline, phenylalanine and aniline- or phenol-fluorine derivatives were synthesized. Their catalytic ability was evaluated in the intermolecular asymmetric aldol reaction, both in organic and aqueous media. Aniline-fluorine derivatives proved to be superior and the best results were obtained, when 2-CF3 aniline was employed. A diverse substrate scope consisting of both aromatic and aliphatic aldehydes, as well as different ketones was demonstrated, where aromatic aldehydes afforded products in high yields (up to 100%) with excellent diastereo- (up to 95:5) and enantioselectivities (up to 97%), whereas the aliphatic aldehydes afforded also excellent selectivities, but relatively low yield. A simple addition of fluorine to a dipeptide analogue affords organocatalysts with new interesting properties that can catalyze the aldol reaction more efficiently.
A Catalyst-Directed Remote Stereogenic Center Switch During the Site-Selective Aldol Desymmetrization of Cyclohexanone-Based Diketones
Nugent, Thomas C.,Spiteller, Peter,Hussain, Ishtiaq,Hussein, Hussein Ali El Damrany,Najafian, Foad Tehrani
, p. 3706 - 3713 (2016)
Site-selectivity, differentiating members of the same functional group type on one substrate, is an emerging tactic for shortened advanced building block and biomolecule synthesis. Despite its potential, site-selectivity remains less studied and especially so for ketone-based substrates. During this work ketone site-selectivity has been coupled with the chiral amine-catalyzed aldol desymmetrization of 4-keto-substituted cyclohexanones, allowing three stereogenic centers to form in the aldol product while leaving the acyclic ketone unreacted. Unique here, compared to all previous 4-substituted cyclohexanone desymmetrizations, is the first access to synthetically useful quantities of an epimeric (remote stereogenic center) aldol product. To demonstrate the value of these aldol products, we show their elaboration into eight keto-acetonide and one keto-lactone products. All compounds were isolated as single diastereomers and in high ee (≥96%). These efforts represent the first full characterization of aldol products with type III, Figure 2, relative stereochemistry, regardless of the enantiomer formed. (Figure presented.).
A green and efficient asymmetric aldol reaction catalyzed by a chiral anion modified ionic liquid
Qian, Yunbo,Zheng, Xin,Wang, Yongmei
, p. 3672 - 3677 (2010)
A chiral anion modified ionic liquid derived from L-proline proves as a green, and efficient asymmetric organocatalyst for direct asymmetric aldol reactions in [BMIm]BF4 at room, temperature. The corresponding aldol products with moderate to go
A tripeptide-like prolinamide-thiourea as an aldol reaction catalyst
Fotaras, Stamatis,Kokotos, Christoforos G.,Kokotos, George
supporting information; experimental part, p. 5613 - 5619 (2012/08/08)
A tripeptide-like prolinamide-thiourea catalyst with (S)-proline, (1S,2S)-diphenylethylenediamine and (S)-di-tert-butyl aspartate as building blocks provides the products of the reaction between ketones and aromatic aldehydes in high to quantitative yields and high stereoselectivities (up to 99:1 dr and 99% ee). Both the chiral centers of the diamine unit are essential, while the thiourea hydrogen originating from the amine and the amide hydrogen play a predominant role for the catalyst efficiency.
