A Novel Electrosynthetic System for Anodic Substitution Reactions by Using Parallel Laminar Flow in a Microflow Reactor

Abstract

We have developed a novel electrosynthetic system for anodic substitution reactions by using parallel laminar flow in a microflow reactor. This system enables nucleophilic reactions to overcome the restraint, such as the oxidation potential of nucleophiles and the stability of cationic intermediates, by the combined use of ionic liquids as reaction media and the parallel laminar flow in the microflow reactor. By using this novel electrosynthetic system, the anodic substitution reaction of carbamates, especially of cyclic carbamates, with allyltrimethylsilane were carried out to provide the corresponding products in moderate to good conversion yields in a single flow-through operation at ambient temperature (without the need for low-temperature conditions).

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…136,137 When the carbamate and the nucleophile are introduced in different streams, mass transfer between these separate streams can only occur via diffusion between the liquid–liquid contact area. Due to the small size of the flow channel, this area will remain stable and laminar.…”

The combined use of a continuous‐flow microchannel reactor and ionic liquid cosolvent for efficient biocatalysis of unpurified recombinant enzyme

“…As expected, the K m of 0.022 g L ‐1 was decreased to approximately one‐third of that in a batch reactor, which indicated the affinity of recombinant RhaB1 with substrates increased. In addition, compared with the batch reactor, the k cat and v max / K m were improved 19.2 and 65.7 times, respectively, which indicated a more efficient reaction between the enzyme and substrate in the microchannel reactor . Typically, the apparent Michaelis constant depends on two factors, the enzyme and the mass transfer rate.…”

“…The microreactor had one T‐shaped inlet channel and one outlet channel. The main channel dimension was 200 µm wide, 100 µm deep and 1 m long, and the channel of the microflow reactor was small enough to ensure that the flow regime is stable and laminar . The reaction substrate at 0.01 g L ‐1 (rutin at pH 5.0 in citric acid‐disodium hydrogen phosphate) and the recombinant RhaB1 solution containing 0.02 g mL ‐1 [Toma][Tf 2 N] were both pumped into the microchannel by a two‐channel syringe pump.…”

Electrochemical microstructured reactors: design and application in organic synthesis

“…This system enables nucleophilic reactions to overcome the restraint, such as the oxidation potential of nucleophiles and the stability of cationic intermediates, by the combined use of ionic liquids as reaction media and the parallel laminar flow in the microflow reactor [50]. By using this novel [50] electrosynthetic system, the anodic substitution reaction of carbamates, especially of cyclic carbamates, with allyltrimethylsilane, as shown in Fig. 15, were carried out to provide the corresponding products in moderate to good yields as shown in Table 7 in a single flow-through operation at ambient temperature (without the need for lowtemperature conditions).…”

“…A summary of the anodic substitution reaction experiments of N-(methoxycarbonyl)pyrolidine with allyltrimethylsilane in the parallel laminar mode[50] The flow rates of the two electrolytic solutions containing A and B, respectively, were fixed at 0.1 mL min -1 each. Current density was 30 A m -2 and the reaction temperature was at 20°C a TFE 2,2,2-trifluoroethanol b [emin][BF 4 ] for 1-ethyl-3-methylimidazonium tetrafluoroborate c [emin][TFSI] for 1-ethyl-3-methylimidazonium bis(trifluoromethanesulfonyl)imide d [deme][TFSI] for N,N-diethyl-N-(2-methoxyethyl)ammonium bis (trifluoromethanesulfonyl)imide…”