Prof. Dong Pyo Kim and Dr. Kyoung-Ik Min Design Microfluidic Device That Outpaces Fries Rearrangement
Chemistry relies on encounters between reactive partners and often involves competition between unimolecular and bimolecular reactivity of an intermediate. Sometimes one of the partners changes shape during the wait, spoiling the desired outcome. For example, rapid intramolecular rearrangements often foil attempts at site-selective bimolecular functionalization.
Prof. Dong Pyo Kim and Dr. Kyoung-Ik Min (Dept. of Chemical Engineering) have designed a polyimide film based microfluidic device that outpaces the very rapid anionic Fries rearrangement to chemoselectively functionalize a product. Central to the technique is a chip microreactor of their design, which can deliver a reaction time in the submillisecond range even at cryogenic temperatures. Their research was published in Science.
The device operates at low temperatures to keep individual reactants from isomerizing. It also achieves fast flow rates to maximize encounters between reactants on a microsecond scale. Prof. Kim and Dr. Min show bimolecular carbon-carbon coupling before one of the reagents can undergo a Fries rearrangement that would shift a neighboring group to the coupling site.
Lastly, the microreactor was applied to the synthesis of an afesal, a bioactive molecule exhibiting anthelmintic activity, to demonstrate its potential for practical synthesis and production.