868696-68-8Relevant academic research and scientific papers
Conformationally stabilized catalysts by fluorine insertion: Tool for enantioselectivity improvement
Quintard, Adrien,Langlois, Jean-Baptiste,Emery, Daniel,Mareda, Jiri,Guenee, Laure,Alexakis, Alexandre
supporting information; experimental part, 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
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
Aminal-pyrrolidine organocatalysts - Highly efficient and modular catalysts for α-functionalization of carbonyl compounds
Quintard, Adrien,Belot, Sebastien,Marchai, Estelle,Alexakis, Alexandre
experimental part, p. 927 - 936 (2010/04/25)
The substitution of the 4-position of hydroxyproline by a phenol group, together with an aminal on the 2-position, gave a synergistic effect leading to two powerful complementary organocatalysts. They show excellent enantiocontrol in the α-functionalization of a wide range of linear/ branched aldehydes and ketones, including Michael additions to ethenediyl disulfones or nitrostyrene and α-amination. We obtained ees up to 98.5 % with low catalyst loadings (down to 1 mol-%). As a proof of efficiency, TOFs of up to 1000 h-1 could be obtained.
Asymmetric addition of α-hetero-disubstituted aldehydes to vinyl sulfones; Formation of highly functionalized tetrasubstituted carbon centres
Quintard, Adrien,Alexakis, Alexandre
supporting information; experimental part, 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 Michael addition of aldehydes to vinyl sulfones: Enantioselective α-alkylations of aldehydes and their derivatives
Zhu, Qiang,Lu, Yixin
supporting information; experimental part, p. 4803 - 4806 (2009/05/31)
(Equation Presented) Organocatalytic asymmetric Michael reaction of unmodified aldehydes to vinyl sulfones catalyzed by silylated biarylprolinol afforded the desired Michael products with exceptional enantioselectivity. The described enantioselective addition to vinyl sulfones, in combination with desulfonation, offers a unique, asymmetric entry to α-alkylated aldehydes and their derivatives.
