1293264-53-5Relevant academic research and scientific papers
Synthesis of 1,4-Dicarbonyl Compounds by Visible-Light-Mediated Cross-Coupling Reactions of α-Chlorocarbonyls and Enol Acetates
Liu, Qiang,Wang, Rui-Guo,Song, Hong-Jian,Liu, Yu-Xiu,Wang, Qing-Min
, p. 4391 - 4396 (2020/09/21)
Herein, we report a protocol for visible-light-mediated radical coupling reactions of α-chloroketones and enol acetates to afford 1,4-dicarbonyl compounds, which are important precursors and intermediates in organic synthesis. The reaction involves photoredox-catalyzed activation of the α-chloroketone upon photoelectron transfer, carbon–chlorine bond cleavage, and coupling of the resulting radical with the carbon–carbon double bond of the enol acetate. This mild protocol has a wide substrate scope and moderate to good yields. (Figure presented.).
Thiazolium-functionalized polystyrene monolithic microreactors for continuous-flow umpolung catalysis
Bortolini, Olga,Cavazzini, Alberto,Dambruoso, Paolo,Giovannini, Pier Paolo,Caciolli, Lorenzo,Massi, Alessandro,Pacifico, Salvatore,Ragno, Daniele
, p. 2981 - 2992 (2013/10/08)
Thiazolium salt pre-catalysts have been immobilized on silica and monolithic polystyrene and their activity was tested under batch conditions in three model umpolung reactions, namely the benzoin condensation of benzaldehyde, the acyloin-type condensation of biacetyl, and the Stetter reaction of biacetyl with trans-chalcone. A prerequisite of the study has been the utilization of environmentally benign water and ethanol solvents. After having established the higher performance of polystyrene monolithic thiazolium carbene catalysts, their effectiveness has been tested under the flow regime by fabricating the corresponding monolithic microreactors (pressure-resistant stainless-steel columns). Importantly, it has been demonstrated by a brief substrate scope study that the polymeric matrix and the continuous flow regime synergistically contribute to preserve the activity of the carbene catalysts over time, thus permitting the long-term operation (up to 7 days) of the prepared monolithic reactors for the production of valuable compounds via the umpolung strategy.
Thiazolium-catalyzed intermolecular Stetter reaction of linear and cyclic alkyl α-diketones
Bortolini, Olga,Fantin, Giancarlo,Fogagnolo, Marco,Giovannini, Pier Paolo,Massi, Alessandro,Pacifico, Salvatore
experimental part, p. 8437 - 8444 (2012/04/10)
An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different linear α-diketones as acyl anion donors (e.g. 3,4-hexanedione for propionyl anion additions). Moreover, the unprecedented umpolung reactivity of cyclic α-diketones in the atom economic nucleophilic acylation of chalcones is herein presented. Mechanistic aspects of the thiazolium-based catalysis involving linear and cyclic α-diketone substrates are also discussed. The Royal Society of Chemistry 2011.
N-Heterocyclic carbene-catalysed intermolecular Stetter reactions of acetaldehyde
Kim, Sun Min,Jin, Ming Yu,Kim, Mi Jin,Cui, Yan,Kim, Young Sug,Zhang, Liqiu,Song, Choong Eui,Ryu, Do Hyun,Yang, Jung Woon
supporting information; experimental part, p. 2069 - 2071 (2011/05/14)
A facile method for the intermolecular Stetter reaction of various Michael acceptors with acetaldehyde as a biomimetic acylanion source was realized using N-heterocyclic carbene catalysis. This catalytic system has also been applied to the enantioselective Stetter reaction and resulted in moderate to good enantioselectivities for the corresponding Stetter products.
