Heterogeneous Jørgensen–Hayashi catalyst for asymmetric Michael addition of malonates to α,β-enals. Cooperative effect with Ca(OTf)2

Silica gel-immobilized multidisciplinary materials applicable in stereoselective organocatalysis and HPLC separation

“…More efficient and already veried supports such as organic polymers [29][30][31][32][33][34][35] or nanoparticles 36,37 have, however, not been considered in this study. The obvious reason is that we aimed for simultaneous use of the new materials as continuous ow organocatalysts and stationary phases for HPLC.…”

“…The current approach to address this problem involves immobilization of the catalyst to a solid support. 28 Several types of solid matrices, such as polystyrene, [29][30][31][32][33][34][35] metal nanoparticles, 36,37 metalorganic frameworks, 38 ion-modied resins for non-covalent binding, [39][40][41] or mesoporous silica [42][43][44][45] have been introduced as solid supports for various types of organocatalysts.…”

New atranes and similar ionic complexes. Synthesis, structure, properties

“…; Y = O, S), by the condensation of (het)aryl‐containing aldehydes with 2‐alkoxy‐ and 2‐alkylthioacetaldehydes . The obtained α,β‐unsaturated aldehydes are highly reactive compounds attracting significant theoretical and practical interest. For example, they were used in the synthesis of various heterocycles and drugs …”

Irina Beletskaya: Chemistry Excellence in Scientific Endeavors

“…This immobilized organocatalyst was also successfully employed in the asymmetric Michael addition of malonates to unsaturated aldehydes, with Lewis acid Ca(OTf) 2 acting as a cocatalyst. 49 Atom-economy and control of reaction selectivity as compared to the other catalytic processes should be also mentioned (Scheme 13). 50 A relatively simple Lewis acid, Cu(ClO 4 ) 2 , in combination with 2,2′-bipyridyl ligand, served as an effective catalyst for the Michael addition of aromatic and heteroaromatic compounds to vinyl phosphonates under mild conditions.…”

“…Careful selection of substituents in the aminating agent led to excellent enantioselectivity (>99% ee). This immobilized organocatalyst was also successfully employed in the asymmetric Michael addition of malonates to unsaturated aldehydes, with Lewis acid Ca­(OTf) 2 acting as a cocatalyst . Atom-economy and control of reaction selectivity as compared to the other catalytic processes should be also mentioned (Scheme ).…”