Synthesis of gem‐Dichlorocyclopropanes Using Liquid–Liquid Slug Flow

Abstract

By analyzing the causes of precipitation and clogging in continuous flow dichlorocyclopropanation, we established that the flow reaction can be performed only with T‐junctions and microtubes. Unlike tertiary amines, when quaternary ammonium salts were used as PTCs, precipitation and clogging in microchannels did not occur, and an excellent yield of up to 99% was obtained after optimizing the reaction temperature, reactant concentration, and retention time. In the scale‐up experiment, the reaction yields slightly decreased as the inner diameter (ID) of the microchannel was increased, but the calculated throughput increased from 2.41 g/h (ID: 1.5 mm) to 3.46 g/h (ID: 1.9 mm) and 5.13 g/h (ID: 2.4 mm)

Direct formation of amide/peptide bonds from carboxylic acids: no traditional coupling reagents, 1-pot, and green

“…, CDI) at scale. 9 This odorless dithiocarbonate (DPDTC) had been made decades ago, 10 and more recently, related albeit limited applications have also been reported by Lee. 11 Preparation of thioester intermediates is typically performed in organic solvents ( e.g.…”

Continuous flow system for biphasic synthesis of gem‐dichloroaziridine derivatives

“…If the short-lived and highly reactive dichlorocarbene cannot rapidly react with imine to form gem-dichloroaziridine, by-products such as carbon monoxide or tar are produced. 13,15 Naeimi et al used sonication and Song et al used a solid-liquid system instead of a liquid-liquid system to resolve these drawbacks. 10,16,17 In both the proposed methods, the interface between the two phases was enlarged and the efficiency of mass transfer increased, leading to a high reaction yield in a short reaction time.…”

“…In conventional batch systems with low interface/volume ratios, the use of PTC cannot guarantee a rapid mass transfer. If the short‐lived and highly reactive dichlorocarbene cannot rapidly react with imine to form gem ‐dichloroaziridine, by‐products such as carbon monoxide or tar are produced 13,15 . Naeimi et al .…”