Recyclable Ruthenium Catalyst for Distal
<i>meta</i>
‐C−H Activation
作者:Isaac Choi、Valentin Müller、Yanhui Wang、Kai Xue、Rositha Kuniyil、Loren B. Andreas、Volker Karius、Johan G. Alauzun、Lutz Ackermann
DOI:10.1002/chem.202003622
日期:2020.11.26
unprecedented hybrid‐ruthenium catalysis for distal meta‐C−H activation. The hybrid‐ruthenium catalyst was recyclable, as was proven by various heterogeneity tests, and fully characterized with various microscopic and spectroscopic techniques, highlighting the physical and chemical stability. Thereby, the hybrid‐ruthenium catalysis proved broadly applicable for meta‐C−Halkylations of among others purine‐based
Enantioselective Addition of α‐Nitroesters to Alkynes
作者:Ryan T. Davison、Patrick D. Parker、Xintong Hou、Crystal P. Chung、Sara A. Augustine、Vy M. Dong
DOI:10.1002/anie.202014015
日期:2021.2.23
By using Rh–H catalysis, we couple α‐nitroesters and alkynes to prepare α‐amino‐acid precursors. This atom‐economical strategy generates two contiguous stereocenters, with high enantio‐ and diastereocontrol. In this transformation, the alkyne undergoes isomerization to generate a RhIII–π‐allyl electrophile, which is trapped by an α‐nitroester nucleophile. A subsequent reduction with In powder transforms
通过使用 Rh-H 催化,我们将 α-硝基酯和炔烃偶联以制备 α-氨基酸前体。这种原子经济策略产生两个连续的立体中心,具有高对映和非对映控制。在这种转化过程中,炔烃经过异构化生成 Rh III -π-烯丙基亲电子试剂,该亲电子试剂被 α-硝基酯亲核试剂捕获。随后用 In 粉末还原将烯丙基 α-硝基酯转化为相应的 α,α-二取代 α-氨基酯。
Absolute configuration and partial asymmetric synthesis of 2-phenyl-1, 1-dimethylcyclopropane
作者:I. Tömösközi
DOI:10.1016/0040-4020(66)80116-3
日期:1966.1
Reaction of optically active styrene oxide with triethyl α-phosphonopropionate gives 2-phenyl-1-methylcyclopropanecarboxylate in optically active form. When the −CO2Et group is transformed into −CH3, the product has but one asymmetric centre originating from styrene oxide. Based on the intramolecular S 2 mechanism of the formation of the cyclopropane ring, the absolute configuration of the title compound
Complete Diastereofacial Selective Cycloaddition of New Sulfinyl Dienophiles (Ss)-and (Rs)-(-)Menthyl α-(2-Methoxyphenylsulfoxyl)acylate with Anthracene Under Chelation Control
作者:Tay-Yuan Chau、Hsaio-Chi Lin、Wenhao Hu
DOI:10.1080/00397919608003539
日期:1996.5
Abstract New sulfinyldienophiles (Ss)- and (Rs)- (-)menthyl α-(2-methoxyphenylsulfoxyl)acylate were prepared. Cycloadditions with anthracene in dichloromethane proceeded with complete diastereoselectivity under chelation control. Chirality at sulfur controlled diastereofacial selectivity.
Visible-Light-Mediated Oxidative Coupling of Vinylarenes with Bromocarboxylates Leading to γ-Ketoesters
作者:Xing-Xiao Fang、Peng-Fei Wang、Wei Yi、Wei Chen、Sheng-Chun Lou、Gong-Qing Liu
DOI:10.1021/acs.joc.9b02310
日期:2019.12.6
A photocatalytic strategy for the synthesis of gamma-ketoesters was reported. Using DMSO as both the solvent and terminal oxidant, oxidative coupling of vinylarenes with bromocarboxylates proceeded readily, giving a variety of gamma-ketoesters in good isolated yields and with a broad functional-group tolerance.