We wish to report our preliminary results on the discovery and development of a catalytic, asymmetric β-hydride elimination from vinyl Pd(II)-complexes derived from enol triflates to access chiral allenes. To achieve this, we developed a class of chiral phosphite ligands that demonstrate high enantioselectivity, allow access of either allene enantiomer, and are readily synthesized. The methodology is demonstrated on over 20 substrates, and application to the formal asymmetric total synthesis of the natural product, (+)-epibatidine, is also provided.
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http://dx.doi.org/10.1021/ja401606e | DOI Listing |
Gen Thorac Cardiovasc Surg Cases
January 2025
Osaka Metropolitan University Graduate School of Medicine, 1-4-3, Asahimachi, Abeno-Ku, Osaka, 545-8585, Japan.
Background: Repair of the regurgitant bicuspid aortic valve is an attractive alternative to valve replacement. Although good long-term outcomes have been reported, postoperative aortic stenosis remains a major late cause of repair failure in bicuspid aortic valves. Sinus plication is effective for creating a more symmetrical commissural angle, leading to a decrease in the mean transvalvular pressure gradient.
View Article and Find Full Text PDFProc Biol Sci
January 2025
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
To maintain stable vision, behaving animals make compensatory eye movements in response to image slip, a reflex known as the optokinetic response (OKR). Although OKR has been studied in several avian species, eye movements during flight are expected to be minimal. This is because vertebrates with laterally placed eyes typically show weak OKR to nasal-to-temporal motion (NT), which simulates typical forward locomotion, compared with temporal-to-nasal motion (TN), which simulates atypical backward locomotion.
View Article and Find Full Text PDFEarly Hum Dev
January 2025
School of Medicine, Atenas University Centre, Prefeito Alberto Moura, 6000, 35701-383 Sete Lagoas, MG, Brazil. Electronic address:
Background: Intrauterine growth restriction (IUGR) is a severe condition in which the fetus fails to reach its genetically predetermined growth potential, impairing prenatal development and predisposing individuals to postnatal consequences that may persist into adulthood. Although fetal mechanisms such as the brain-sparing effect have been proposed to protect the brain against IUGR-related deficits, the extent of this protection remains unclear.
Objective: To conduct a systematic review that demonstrates prenatal morphofunctional abnormalities in the brain of individuals with IUGR.
Sci Rep
January 2025
Department of Mechanical Engineering, Seoul National University, Seoul, 08826, Korea.
In the present study, we experimentally investigate the liquid flow induced in a rotating drum (cylindrical tank with a short aspect ratio) aligned horizontally, focusing on the variation in the time-averaged and fluctuating flow structures with different fill ratios. For each fill ratio, controlled by varying the water height, we measure the velocity fields at different cross-sectional planes with particle image velocimetry while varying the rotational speed of the drum. Compared to the condition of a fill ratio of 1.
View Article and Find Full Text PDFAnal Chem
January 2025
Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
This study tackles the challenge of enantiodifferentiation of nitrile compounds, which is typically difficult to resolve using nuclear magnetic resonance (NMR) due to the significant distance between the chiral center and the nitrogen atom involved in molecular interactions. We have developed novel chiral F-labeled probes, each featuring two chiral centers, to exploit the "match-mismatch" effect, thereby enhancing enantiodiscrimination. This strategy effectively differentiates chiral analytes with quaternary chiral carbon centers as well as those with similar substituents at the chiral center.
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