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5‐Diethylboryl‐2,3′‐bipyridine (1), which is inaccessible by conventional batch methods, was synthesized by using a flow microreactor. Compound 1 was obtained as an equilibrium mixture of a cyclic trimer and a cyclic tetramer in solution, the latter of which was crystallized in benzene by vapor diffusion of hexane at 7 °C. The dynamic nature of this system was confirmed by solvent‐ and concentration‐dependent experiments. Notably, the dynamics was verified by using flow NMR spectroscopy, which revealed that the time required to reach equilibrium was influenced by the solvent ratio (<18 s, 24–28 s, and 34–42 s in 2 : 1, 1 : 1, and 1 : 2 mixtures of [D6]acetone and C6D6, respectively). Compound 1 and 3‐[4′‐(diethylboryl)phenyl]pyridine (2) exhibited different self‐assembly behavior in solution and crystals. Density functional theory calculations suggested that this difference was largely due to enhanced planarity between two consecutive aromatic rings. [ABSTRACT FROM AUTHOR]

Flash (extremely fast) electrochemical generation of unstable arylbis(arylthio)sulfonium triflates [ArS(ArSSAr)]+ [OTf]− that are unsuitable for accumulation in batch processes was achieved within 10 s in a divided-type flow electrochemcial reactor, enabling one-flow access to vinyl triflates, short-lived oxocarbenium triflates and glycosyl triflates. [ABSTRACT FROM AUTHOR]

A novel flow electrochemical reactor that accomplishes electrolysis within a few seconds in a single passage was developed. By using the flow reactor system, the flash electrochemical generation of short‐lived carbocations, including oxocarbenium ions, N‐acyliminium ions, glycosyl cations, and Ferrier cations was achieved within a few seconds, enabling the subsequent reaction with nucleophiles before their decomposition. Moreover, continuous operation based on the present system enabled the rapid synthesis of pharmaceutical precursors on demand. [ABSTRACT FROM AUTHOR]

A novel flow electrochemical reactor that accomplishes electrolysis within a few seconds in a single passage was developed. By using the flow reactor system, the flash electrochemical generation of short‐lived carbocations, including oxocarbenium ions, N‐acyliminium ions, glycosyl cations, and Ferrier cations was achieved within a few seconds, enabling the subsequent reaction with nucleophiles before their decomposition. Moreover, continuous operation based on the present system enabled the rapid synthesis of pharmaceutical precursors on demand. [ABSTRACT FROM AUTHOR]

Cationic polymerization of vinyl ethers using a multifunctional dendritic initiator and multifunctional terminators in a flow microreactor system gave polymers having multiple functionalities on both ends. Subsequent transformation of the resulting polymers through Suzuki-Miyaura coupling and/or copper-mediated azide-alkyne cycloaddition gave linear-dendritic hybrid polymers. [ABSTRACT FROM AUTHOR]

Cationic polymerization of vinyl ethers initiated by an electrogenerated dendritic diarylcarbenium ion in the presence of 2,6-di- tert -butylpyridine was developed using a flow microreactor. The carbocationic polymer end generated by polymerization of isobutyl vinyl ether was effectively trapped by various nucleophiles such as trimethyl(1-phenylvinyloxy)silane and allyltrimethylsilane to give polymers with very narrow molecular weight distribution. The block copolymerization of two vinyl ethers followed by trapping with nucleophiles was successfully accomplished to give structurally well-defined macromolecules. [ABSTRACT FROM AUTHOR]

• A novel strategy to increase the unit-time-productivity of flow synthesis. • Using hierarchical bimodal porous silica gel (HBPSG) supported palladium column reactors. • The column reactors with low pressure drop enabling high-volume production. • Demonstrated flow synthesis of the precursor of adapalene, a pharmaceutical compound, at 5 g/h. To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. [Display omitted] We describe a novel strategy to increase the unit-time-productivity of flow synthesis by using hierarchical bimodal porous silica gel (HBPSG) supported palladium column reactors. Because HBPSG has a significantly large surface area, the column reactors have low pressure drop, enabling high-volume production. We demonstrated flow synthesis of the precursor of adapalene, a pharmaceutical compound, at 5 g/h which is over 10-fold greater productivity than previous approaches. [ABSTRACT FROM AUTHOR]

In a flow microreactor, aryllithiums bearing a piperidylmethyl group were generated using nBuLi by precise residence time control and effective temperature control, and then selectively borylated with boronic esters such as 2‐isopropoxy‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane (BpinOiPr) and trimethyl borate B(OMe)3 by fast mixing. Moreover, the direct integration with Suzuki–Miyaura cross coupling were successfully achieved to obtain nitrogen‐containing biaryl compounds. The present method could be applied for the straightforward synthesis of the key intermediate of a bioactive component bearing a piperidylmethyl‐biphenyl framework. [ABSTRACT FROM AUTHOR]

The transformation of glycals into 2,3‐unsaturated glycosyl derivatives, reported by Ferrier in 1962, is supposed to involve an α,β unsaturated glycosyl cation, an elusive ionic species that has still to be observed experimentally. Herein, while combination of TfOH and flow conditions failed to observe this ionic species, its extended lifetime in superacid solutions allowed its characterization by NMR‐based structural analysis supported by DFT calculations. This allyloxycarbenium ion was further exploited in the Ferrier rearrangement to afford unsaturated nitrogen‐containing C‐aryl glycosides and C‐alkyl glycosides under superacid and flow conditions, respectively. [ABSTRACT FROM AUTHOR]

The transformation of glycals into 2,3‐unsaturated glycosyl derivatives, reported by Ferrier in 1962, is supposed to involve an α,β unsaturated glycosyl cation, an elusive ionic species that has still to be observed experimentally. Herein, while combination of TfOH and flow conditions failed to observe this ionic species, its extended lifetime in superacid solutions allowed its characterization by NMR‐based structural analysis supported by DFT calculations. This allyloxycarbenium ion was further exploited in the Ferrier rearrangement to afford unsaturated nitrogen‐containing C‐aryl glycosides and C‐alkyl glycosides under superacid and flow conditions, respectively. [ABSTRACT FROM AUTHOR]

Flow microreactors enabled the successful generation of various functional alkyllithiums containing electrophilic functional groups, as well as the use of these alkyllithiums in subsequent reactions. The high reactivity of these series of reactions could be achieved by the extremely accurate and selective control of residence time. Moreover, integrated flow microreactor systems could be used to successfully synthesize heterotelechelic polymers with two functionalities, one at each end, via a process involving controlled anionic polymerization initiated by functional alkyllithium compounds, followed by trapping reactions with difunctional electrophiles. [ABSTRACT FROM AUTHOR]

Synthesis of ketones containing various functional groups from acid chlorides bearing electrophilic functional groups and functionalized organolithiums was achieved using a flow microreactor system. Extremely fast mixing is important for high chemoselectivity. Selective synthesis of ketones can be achieved by extremely fast 1:1 micromixing of acid halides and organolithiums using a flow microreactor system. Moreover, the chemoselective reactions of acid chlorides bearing electrophilic functional groups with functionalized organolithiums were also carried out in this controlled system to give the corresponding functionalized ketones (see scheme). [ABSTRACT FROM AUTHOR]

B A few-millisecond chemistry approach b , conducting a series of reactions with short-lived intermediates in a flow microreactor, enabled chemical conversions involving alkyllithiums bearing an electrophilic functional group, which are virtually impossible with conventional macro batch reactors. B A few-millisecond chemistry approach b , conducting a series of reactions with short-lived intermediates in a flow microreactor, enabled chemical conversions involving alkyllithiums bearing an electrophilic functional group, which are virtually impossible with conventional macro batch reactors. [Extracted from the article]

Invited for the cover of this issue is the group of Aiichiro Nagaki at Kyoto University. The image depicts the reaction in the flow microreactor reported in the paper. Read the full text of the article at10.1002/chem.201902867. [ABSTRACT FROM AUTHOR]

The space integration of the lithiation of aryl halides, the borylation of aryllithiums, and Suzuki–Miyaura coupling using a Pd catalyst supported by a polymer monolith flow reactor without using an intentionally added base was achieved. To scale up the process, a series connection of the monolith Pd reactor was examined. To suppress the increase in the pressure drop caused by the series connection, a monolith reactor having larger pore sizes was developed by varying the temperature of the monolith preparation. The monolithic Pd reactor having larger pore sizes enabled Suzuki–Miyaura coupling at a higher flow rate because of a lower pressure drop and, therefore, an increase in productivity. The present study indicates that series connection of the reactors with a higher flow rate serves as a good method for increasing the productivity without decreasing the yields. [ABSTRACT FROM AUTHOR]