Enantioselective Synthesis of Cyclopropanone Equivalents and Application to the Formation of Chiral β‐Lactams
作者:Christopher M. Poteat、Yujin Jang、Myunggi Jung、J. Drake Johnson、Rachel G. Williams、Vincent N. G. Lindsay
DOI:10.1002/anie.202006786
日期:2020.10.12
derivatives have long been considered unsustainable synthetic intermediates because of their extreme strain and kinetic instability. Reported here is the enantioselective synthesis of 1‐sulfonylcyclopropanols, as stable yet powerful equivalents of the corresponding cyclopropanone derivatives, by α‐hydroxylation of sulfonylcyclopropanes using a bis(silyl) peroxide as the electrophilic oxygen source. This
Nucleophilic addition reactions of soft carbon nucleophiles to nitrones in a flow microreactor are reported for the first time. Under microflow conditions at 30 to 0 °C, a range of nitrones can be efficiently transformed into the corresponding oxyiminium ions by reaction with either acyl halides or trialkylsilyl triflates. These can subsequently undergo the addition of nucleophiles including allyltributylstannane
首次报道了在流动微反应器中软碳亲核试剂与硝酮的亲核加成反应。在 30 至 0 °C 的微流条件下,通过与酰卤或三烷基甲硅烷基三氟甲磺酸酯反应,可以将一系列硝酮有效地转化为相应的氧亚胺离子。这些随后可以添加亲核试剂,包括烯丙基三丁基锡烷、烯酮甲基叔丁基二甲基甲硅烷基乙缩醛和 N-甲硅烷基烯酮亚胺,以高产率提供相应的加合物;由于不希望有的副反应,在类似温度下在分批条件下的此类反应导致较低的产率。
Design of Modified Amine Transfer Reagents Allows the Synthesis of α-Chiral Secondary Amines via CuH-Catalyzed Hydroamination
作者:Dawen Niu、Stephen L. Buchwald
DOI:10.1021/jacs.5b05446
日期:2015.8.5
were used for the synthesis of chiral secondaryamines, competitive, nonproductive consumption of these reagents by the CuH species resulted in poor yields. In this paper, we report the design of a modified type of amine transfer reagent that addresses this limitation. This effort has enabled us to develop a CuH-catalyzed synthesis of chiral secondaryamines using a variety of amine coupling partners,
Rhodium-catalyzed Electrophilic Amination of Arylboronic Acids with Secondary Hydroxylamines
作者:Tomohiro Yasuhisa、Koji Hirano、Masahiro Miura
DOI:10.1246/cl.161158
日期:2017.4.5
A rhodium(III)-catalyzed electrophilicamination of arylboronic acids with secondary hydroxylamines has been developed. The rhodium catalysis is compatible with heteroarylboronic acids as well as acyl and alkoxycarbonyl protecting groups on the nitrogen of O-acylhydroxylamines, and the corresponding secondary anilines are obtained in good to excellent yields.
A simple method for the oxidn. of primaryamines to the corresponding ketones in the presence of both moisture and air is described. Treatment of an amine with benzoyl peroxide in the presence of Cs2CO3, followed by warming of the hydroxylamine product to 50-70° leads directly to the ketone. The method is shown to be effective for both benzylic and aliph. substrates. [on SciFinder(R)]