1250871-59-0Relevant academic research and scientific papers
Dynamic Control of Chiral Space Through Local Symmetry Breaking in a Rotaxane Organocatalyst
Dommaschk, Marcel,Echavarren, Javier,Leigh, David A.,Marcos, Vanesa,Singleton, Thomas A.
, p. 14955 - 14958 (2019/11/05)
We report on a switchable rotaxane molecular shuttle that features a pseudo-meso 2,5-disubstituted pyrrolidine catalytic unit on the axle whose local symmetry is broken according to the position of a threaded benzylic amide macrocycle. The macrocycle can
1,2-Sulfone rearrangement in organocatalytic reactions
Quintard, Adrien,Alexakis, Alexandre
experimental part, p. 1407 - 1418 (2011/04/18)
The 1,2-sulfone rearrangement resulting from nucleophilic addition to bis activated vinyl-sulfones has been studied in more detail. Various nucleophiles activated by different types of catalysts (enamine, Broensted base, thiourea) are able to promote such
A new class of structurally rigid tricyclic chiral secondary amine organocatalyst: Highly enantioselective organocatalytic Michael Addition of aldehydes to vinyl sulfones
Xiao, Jian,Lu, Yun-Peng,Liu, Yan-Ling,Wong, Poh-Shen,Loh, Teck-Peng
scheme or table, p. 876 - 879 (2011/04/27)
A new class of chiral secondary amine organocatalyst was rationally designed as an efficient catalyst to catalyze the elusive Michael addition of aldehydes to vinyl sulfones. High yield and excellent enantioselectivities could be obtained at room temperature without having to resort to high catalyst loading, anhydrous solvents, and low temperatures. Efficient control of enamine conformation and face shielding as well as the rigid nature of the tricyclic skeleton, with an inherent chiral pocket, provide a well-organized chiral environment to effect this elusive reaction efficiently.(Figure Presented)
Conformationally stabilized catalysts by fluorine insertion: Tool for enantioselectivity improvement
Quintard, Adrien,Langlois, Jean-Baptiste,Emery, Daniel,Mareda, Jiri,Guenee, Laure,Alexakis, Alexandre
scheme or table, p. 13433 - 13437 (2012/01/05)
F rigid cats: The power of conformationally stabilized catalysts is demonstrated. By taking appropriate advantage of fluorine insertion (see scheme), purely conformational catalyst design led to a notable improvement in enantioselectivities from around 70% to 91-98.5% ee. The other advantage of this approach is the better understanding of the origin of the stereoselectivity in the given catalytic system. Copyright
The organocatalytic enantioselective michael addition of aldehydes to vinyl sulfones in water
Xiao, Jian,Liu, Yan-Ling,Loh, Teck-Peng
experimental part, p. 2029 - 2032 (2010/10/03)
The first organocatalytic enantioselective Michael addition of aldehydes to vinyl sulfones in water was achieved using our rationally designed organocatalyst. The rigid nature of the tricycle with an inherent chiral pocket provides a well-organized chiral environment, which together with the hydrophobic pocket, enabled this elusive reaction to proceed smoothly in water. Georg Thieme Verlag Stuttgart.
Asymmetric addition of α-hetero-disubstituted aldehydes to vinyl sulfones; Formation of highly functionalized tetrasubstituted carbon centres
Quintard, Adrien,Alexakis, Alexandre
supporting information; scheme or table, p. 4085 - 4087 (2010/09/06)
Aminal-pyrrolidine catalysed addition of α-hetero-disubstituted aldehydes to vinyl sulfones is described in high enantioselectivity (ee up to 97%). The obtained adducts can easily be converted to enantioenriched synthons as for example 2,2-dialkylepoxide. Evidence for a kinetic resolution is also observed.
Enantioselective organocatalytic conjugate addition of aldehydes to vinyl sulfones and vinyl phosphonates as challenging michael acceptors
Sulzer-Mosse, Sarah,Alexakis, Alexandre,Mareda, Jiri,Bollot, Guillaume,Bernardinelli, Gerald,Filinchuk, Yaroslav
supporting information; experimental part, p. 3204 - 3220 (2009/12/03)
Chiral amines with a pyrrolidine framework catalyze the enantioselective conjugate addition of a broad range of aldehydes to various vinyl sulfones and vinyl phosphonates in high yields and with enantioselectivities up to >99% ee. This novel process provides synthetically useful chiral γ-gem-sulfonyl or phosphonyl aldehydes which can be widely functionalized with retention of the enantiomeric excess. Mechanistic insights including DFT calculations are explored in detail.
Organocatalytic addition on l,2-bis(sulfone)vinylenes leading to an unprecedented rearrangement
Quintard, Adrien,Alexakis, Alexandre
supporting information; experimental part, p. 11109 - 11113 (2010/04/29)
A study was conducted to demonstrate the use of 1,2-bis(sulfone)vinylenes in enamine catalysis. It was revealed that these sulfones led to a new rearrangement arising from a sulfone shift to the adjacent carbon atom. Investigations also revealed that the use of cheaper (Z)-1,2-bis(sulfone) vinylene lead to full conversion after a short reaction time in dioxane, using H2O as co-catalyst to accelerate the reaction. A careful NMR investigation indicated that the new product was gem-disulfone, which was supported by authentic sample.
Highly enantioselective conjugate additions of aldehydes to vinyl sulfones
Landa, Aitor,Maestro, Miguel,Masdeu, Carme,Puente, Angel,Vera, Silvia,Oiarbide, Mikel,Palomo, Claudio
supporting information; experimental part, p. 1562 - 1565 (2009/10/01)
The use of less basic chiral amine catalysts for highly enantioselective conjugate additions of aldehydes to vinyl sulfones was reported. The results show that the addition of aldehydes to α-cyano vinyl sulfones takes place at -40°C to give alcohols. The
