Asymmetric C–H Activation for the Synthesis of P- and Axially Chiral Biaryl Phosphine Oxides by an Achiral Cp*Ir Catalyst with Chiral Carboxylic Amide

ACS Catalysis ◽  
2021 ◽  
pp. 193-199
Author(s):  
Chao-Wei Zhang ◽  
Xian-Qi Hu ◽  
Yuan-Hao Dai ◽  
Peng Yin ◽  
Chuanyong Wang ◽  
...  
2018 ◽  
Vol 57 (39) ◽  
pp. 12901-12905 ◽  
Author(s):  
Yun-Suk Jang ◽  
Łukasz Woźniak ◽  
Julia Pedroni ◽  
Nicolai Cramer

2018 ◽  
Vol 130 (39) ◽  
pp. 13083-13087 ◽  
Author(s):  
Yun-Suk Jang ◽  
Łukasz Woźniak ◽  
Julia Pedroni ◽  
Nicolai Cramer

Author(s):  
Primali Navaratne ◽  
Jenny Wilkerson ◽  
Kavindri Ranasinghe ◽  
Evgeniya Semenova ◽  
Lance McMahon ◽  
...  

<div> <div> <div> <p>Phytocannabinoids, molecules isolated from cannabis, are gaining attention as promising leads in modern medicine, including pain management. Considering the urgent need for combating the opioid crisis, new directions for the design of cannabinoid-inspired analgesics are of immediate interest. In this regard, we have hypothesized that axially-chiral-cannabinols (ax-CBNs), unnatural (and unknown) isomers of cannabinol (CBN) may be valuable scaffolds for cannabinoid-inspired drug discovery. There are multiple reasons for thinking this: (a) ax-CBNs would have ground-state three-dimensionality akin to THC, a key bioactive component of cannabis, (b) ax-CBNs at their core structure are biaryl molecules, generally attractive platforms for pharmaceutical development due to their ease of functionalization and stability, and (c) atropisomerism with respect to phytocannabinoids is unexplored “chemical space.” Herein we report a scalable total synthesis of ax-CBNs, examine physical properties experimentally and computationally, and provide preliminary behavioral and analgesic analysis of the novel scaffolds. </p> </div> </div> </div>


2020 ◽  
Author(s):  
Ziqing Zuo ◽  
Raphael Kim ◽  
Donald Watson

<div><p>We report an asymmetric Ullmann-type homocoupling of <i>ortho-</i>(iodo)arylphosphine oxides and <i>ortho</i>-(iodo)arylphosphonates that results in highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates in good yields and excellent enantioselectivities. These products are readily converted to enantioenriched biaryl bisphosphines without need for chiral auxiliaries or optical resolution. This process provides a straightforward and practical route for the development of previously uninvestigated atroposelective biaryl bisphosphine ligands.</p></div>


2015 ◽  
Vol 19 (5) ◽  
pp. 469-474 ◽  
Author(s):  
Nicholas Bewick ◽  
Agata Arendt ◽  
Yan Li ◽  
S.awomir Szafert ◽  
Tadeusz Lis ◽  
...  

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.


2019 ◽  
Vol 21 (2) ◽  
pp. 503-507 ◽  
Author(s):  
Pei Zhang ◽  
Qiuhong Huang ◽  
Yuyu Cheng ◽  
Rongshi Li ◽  
Pengfei Li ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1196
Author(s):  
György Keglevich

The purpose of this review is to summarize the importance of microwave (MW) irradiation as a kind of catalyst in organophosphorus chemistry. Slow or reluctant reactions, such as the Diels-Alder cycloaddition or an inverse-Wittig type reaction, may be performed efficiently under MW irradiation. The direct esterification of phosphinic and phosphonic acids, which is practically impossible on conventional heating, may be realized under MW conditions. Ionic liquid additives may promote further esterifications. The opposite reaction, the hydrolysis of P-esters, has also relevance among the MW-assisted transformations. A typical case is when the catalysts are substituted by MWs, which is exemplified by the reduction of phosphine oxides, and by the Kabachnik–Fields condensation affording α-aminophosphonic derivatives. Finally, the Hirao P–C coupling reaction may serve as an example, when the catalyst may be simplified under MW conditions. All of the examples discussed fulfill the expectations of green chemistry.


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