860994-76-9Relevant academic research and scientific papers
Enantioselective organocatalytic reduction of β-trifluoromethyl nitroalkenes: An efficient strategy for the synthesis of chiral β-trifluoromethyl amines
Massolo, Elisabetta,Benaglia, Maurizio,Orlandi, Manuel,Rossi, Sergio,Celentano, Giuseppe
, p. 3589 - 3595 (2015)
An efficient organocatalytic stereoselective reduction of β-trifluoromethyl-substituted nitroalkenes, mediated by 3,5-dicarboxylic ester-dihydropyridines (Hantzsch ester type), has been successfully developed. A multifunctional thiourea-based (S)-valine d
Stereoselective nucleophilic addition to imines catalyzed by chiral bifunctional thiourea organocatalysts
Puglisi, Alessandra,Benaglia, Maurizio,Annunziata, Rita,Rossi, Davide
experimental part, p. 2258 - 2264 (2009/04/04)
A new and easy synthesis of chiral bifunctional organic catalysts obtained by the combination of (S)-t-leucine-derivatives with (1R,2R)-trans-1,2-diamino-cyclohexane was developed. A few compounds, representatives of a class of organocatalysts containing a thiourea group and a tertiary amino group connected through a chiral backbone, have been successfully synthesized. The catalytic behaviour of such bifunctional chiral molecules, either neutral or protonated species, was investigated in the addition of acetylacetone to β-nitrostyrene as a model reaction. Using the best conditions, high yields and enantioselectivities of up to 85% were obtained. The same metal free catalysts were then employed in the addition of activated nucleophiles to imines: in the reaction of 1,3-diketones with N-CBz imines, the products were isolated in up to 61% ee, while in the reaction with diethyl malonate enantioselectivities up to 71% were reached.
Structural optimization of thiourea-based bifunctional organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones
Berkessel, Albrecht,Mukherjee, Santanu,Mueller, Thomas N.,Cleemann, Felix,Roland, Katrin,Brandenburg, Marc,Neudoerfl, Joerg-M.,Lex, Johann
, p. 4319 - 4330 (2008/09/18)
This article describes the synthesis of a library of structurally diverse bifunctional organocatalysts bearing both a quasi-Lewis acidic (thio)urea moiety and a Bronsted basic tertiary amine group. Sequential modification of the modular catalyst structure and subsequent screening of the compounds in the alcoholytic dynamic kinetic resolution (DKR) of azlactones revealed valuable structure-activity relationships. In particular, a "hit-structure" was identified which provides e.g. N-benzoyl-tert-leucine allyl ester in an excellent enantiomeric excess of 95%. The Royal Society of Chemistry 2006.
