9-Amino-(9-deoxy)cinchona alkaloid-derived new chiral phase-transfer catalysts
作者:Wenwen Peng、Jingwei Wan、Bing Xie、Xuebing Ma
DOI:10.1039/c4ob01648c
日期:——
9-amino-(9-deoxy)cinchona alkaloid-derived chiralphase-transfercatalysts bearing amino groups was developed by using known cinchona alkaloids as the starting materials. Due to the transformation of the 9-hydroxyl group into a 9-amino functional group, the catalytic performances were significantly improved in comparison with the corresponding first generation phase-transfercatalysts, and excellent yields (92–99%)
We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogues, in which all stereocenters were controlled by a catalytic asymmetric phase-transfer reaction and epoxidation. Furthermore, drastic counteranion effects in phase-transfer catalysis were observed for the first time, making it possible to three-dimensionally fine-tune the catalyst (ketal part, aromatic
was used in phase-transfer alkylations and Michael additions to afford various opticallyactive α-amino acid equivalents in up to 93% yield. Moreover, dramatic counter anion effects were observed in phase-transfer catalysis (PTC) for the first time, making it possible to further improve reactivity and selectivity. These findings validate the usefulness of three-dimensional fine-tuning of the catalyst
Beschleunigung von zweiphasiger Biokatalyse durch neue Prozessfenster
作者:Florence Huynh、Matthew Tailby、Aled Finniear、Kevin Stephens、Rudolf K. Allemann、Thomas Wirth
DOI:10.1002/ange.202005183
日期:——
Reaktionen demonstriert wird. Diese Methode ermöglicht auch die Intensivierung biokatalytischer Reaktionen, wie durch Veresterungen mithoher Ausbeute und mit der Sesquiterpencyclase‐katalysierten Synthese von Sesquiterpenen aus Farnesyldiphosphat als hochwertige Naturstoffe mit Anwendungen in der Medizin, Landwirtschaft und Duftstoffindustrie gezeigt wird. Die Produktfreisetzung in Sesquiterpensynthasen
摘要Prozessintensivierung durch kontinuierliche Flussreaktionen hat die Produktionsraten von Feinchemikalien und Pharmazeutika deutlich erhöht。催化反应是一种非常规和特殊的方法,适用于 Hochleistungs-Flüssig/Flüssig-Gegenstrom 色谱系统。Produkte werden erheblich schneller 还属于 Herkömmlichen Batch-Reaktoren 或分段式 Durchflusssystemen gebildet,是一种立体选择性相转移催化反应演示器。强化生物催化反应的方法,以及倍半萜环化酶-催化剂合成的倍半萜烯合成方法工业区 倍半萜合成物中的产品是一种疏水性物质,其本质是倍半萜的限制,它
Improved Access to Chiral Tetranaphthoazepinium-Based Organocatalysts Using Aqueous Ammonia as Nitrogen Source
bromides has found wide application as highly efficient C2-symmetrical phase-transfercatalysts (PTCs, Maruoka typecatalysts). Unfortunately, the synthesis requires a large number of steps and hampers the build-up of catalyst libraries which are often desired for screening experiments. Here, we present a more economic strategy using dinaphthoazepine 7 as the common key intermediate. Only at this stage