1. Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification
- Author
-
Giancarlo Fantin, Pier Paolo Giovannini, Daniele Ragno, Carmela De Risi, Anna Zaghi, Graziano Di Carmine, Alessandro Massi, and Olga Bortolini
- Subjects
Base (chemistry) ,continuos-flow ,010402 general chemistry ,01 natural sciences ,Full Research Paper ,lcsh:QD241-441 ,Electron transfer ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Benzoin ,C–C coupling ,diketone ,electron-transfer ,umpolung ,Organic chemistry ,lcsh:Science ,chemistry.chemical_classification ,Polarity reversal ,Packed bed ,010405 organic chemistry ,Organic Chemistry ,Ambientale ,0104 chemical sciences ,Solvent ,Chemistry ,chemistry ,Chemical engineering ,lcsh:Q ,Polystyrene ,Microreactor - Abstract
A convenient heterogeneous continuous-flow procedure for the polarity reversal of aromatic α-diketones is presented. Propaedeutic batch experiments have been initially performed to select the optimal supported base capable to initiate the two electron-transfer process from the carbamoyl anion of the N,N-dimethylformamide (DMF) solvent to the α-diketone and generate the corresponding enediolate active species. After having identified the 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine on polystyrene (PS-BEMP) as the suitable base, packed-bed microreactors (pressure-resistant stainless-steel columns) have been fabricated and operated to accomplish the chemoselective synthesis of aroylated α-hydroxy ketones and 2-benzoyl-1,4-diones (benzoin- and Stetter-like products, respectively) with a good level of efficiency and with a long-term stability of the packing material (up to five days).
- Published
- 2016