Diastereodifferentiating [2+2] photocycloaddition of chiral cyclohexenone carboxylates with cyclopentene by a microreactor

Terao, Ken; Nishiyama, Yasuhiro; Aida, Shin; Tanimoto, Hiroki; Morimoto, Tsumoru; Kakiuchi, Kiyomi

doi:10.1016/j.jphotochem.2012.05.021

Cited by 32 publications

(18 citation statements)

References 29 publications

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“…In order to accomplish compatibility enhancing both reaction efficiency and stereoselectivity, we conducted the photoreaction with liquid olefin (cyclopentene) instead of gas olefin (ethylene) at 0 °C ( Scheme 3 ). Though this photoreaction of 3a should produce four diastereomeric isomers of photoadducts, cis-syn-cis products 6a , 7a and cis-anti-cis products 8 a , 9 a in organic solvents, only three products ( 6 , 8 , and 9 ) were observed as previous reported ( Table 2 , entries 10–12) [ 23 ]. The photoreaction of 3b also gave only three products (compounds 6b , 8b , and 9b ) in organic solvent ( Table 2 , entries 22–24).…”

Section: Resultssupporting

confidence: 66%

Diastereoselective [2+2] Photocycloaddition of Chiral Cyclic Enones with Olefins in Aqueous Media Using Surfactants

et al. 2013

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We conducted diastereodifferentiating [2+2] photocycloadditions of cyclo-hexenones modified with a chiral 8-(p-methoxy phenyl)menthyl auxiliary with olefins in water. Although the photoreaction didn’t proceed at all in pure water owing to very low solubility, the use of surfactants [sodium dodecyl sulfate (SDS) or dodecylamine hydrochloride (DAH)] and additive (organic solvent) enabled the reactions to progress with moderate to high conversions and yields. Furthermore, we synthesized a new menthol derivative substrate containing a (p-octyloxy)phenyl group for enhancing hydrophobicity, and elucidated that this new substrate was found to be a suitable chiral auxiliary in this asymmetric photoreaction in aqueous system. The additive effect of organic molecules on the yield and diastereoselectivity of the photo-adducts is also discussed.

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Section: Resultssupporting

confidence: 66%

Diastereoselective [2+2] Photocycloaddition of Chiral Cyclic Enones with Olefins in Aqueous Media Using Surfactants

et al. 2013

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“…While embedded reactors with fixed volumes were chosen in earlier studies, flexible capillary‐based reactors are now more common. Dedicated reactor systems have likewise been developed for micro‐scale synthesis 22, 23 as well as meso‐scale production 24–26. An alternative reactor system has been recently developed by Vapourtec Ltd. in the UK.…”

Section: Introductionmentioning

confidence: 99%

Photodecarboxylations in an Advanced Meso‐Scale Continuous‐Flow Photoreactor

2015

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Selected photodecarboxylations of phthalimides were realized under continuousflow conditions using an advanced meso-scale photoreactor. The improved efficiency, yields, and productivities of these photochemical reactions highlight the benefits of using flow as opposed to conventional batch operation modes. Flow chemistry furthermore allows for an easy combination of multiple reaction steps in series. This is demonstrated by the successful synthesis of a pharmaceutical target molecule through a tandem photochemical-thermal procedure carried out in uninterrupted flow.

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“…Transparency allows chemical engineers to easily monitor and control reaction conditions or high photocatalytic performance. [48,57] Hence, microreactors used in enantiomer synthesis can be categorized based on their building materials.…”

Section: Continuous-flow Microreactors For Enantiomer and Diastereoisomer Synthesismentioning

confidence: 99%

“…Various types of microfluidic devices have been used for optical enantiomer and diastereoisomer production. The most straightforward options are microcapillaries with internal diameters ranging from hundreds of microns to millimeters connected by commercially available PEEK (polyether ether ketone) or steel connectors, among other materials, [17][18][19]38,39,41,[47][48][49][51][52][53][57][58][59][60]66,69] as shown in Figure 1(a). Fluoropolymers, such as PTFE (polytetrafluoroethylene), [18,38,39,49,53,58,66] perfluoroalkoxy polymer, [52] and fluorinated ethylene-propylene, [17] remain the most popular microcapillary materials for their excellent chemical resistance and relatively high melting points.…”

Section: Reactor Materials and Designmentioning

confidence: 99%

Microreaction and membrane technologies for continuous single-enantiomer production: A review

et al. 2021

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Microreaction and membrane technologies offer optimal conditions for controlling enantiomer synthesis and purification processes in continuous production, with numerous advantages over batch manufacturing. One of the many forces driving the development of such technologies for the production of single optical isomers is the need for enantiomerically pure pharmaceutical drugs because enantiomers may display opposite therapeutic effects or different treatment efficacies and side effects. Yet, despite advances in asymmetric synthesis and separation techniques, preparing enantiomerically pure compounds remains a challenging task. Here, we review the progress in microfluidics and membrane chiral separation over the last two decades. In addition to describing and critically assessing the state of the art in both disciplines, we provide an overview of their beneficial properties and characteristics for developing technologies toward producing enantiomerically pure compounds. Concomitantly, we evaluate efforts to integrate synthesis and membrane separation into a microfluidic platform and pinpoint the limiting factors that must be overcome before these platforms can be fully deployed in the industry.

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Diastereodifferentiating [2+2] photocycloaddition of chiral cyclohexenone carboxylates with cyclopentene by a microreactor

Cited by 32 publications

References 29 publications

Diastereoselective [2+2] Photocycloaddition of Chiral Cyclic Enones with Olefins in Aqueous Media Using Surfactants

Diastereoselective [2+2] Photocycloaddition of Chiral Cyclic Enones with Olefins in Aqueous Media Using Surfactants

Photodecarboxylations in an Advanced Meso‐Scale Continuous‐Flow Photoreactor

Microreaction and membrane technologies for continuous single-enantiomer production: A review

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