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241.
Bos PH Rudolph A Pérez M Fañanás-Mastral M Harutyunyan SR Feringa BL 《Chemical communications (Cambridge, England)》2012,48(12):1748-1750
A highly efficient method is reported for the asymmetric ring opening of oxabicyclic alkenes with organolithium reagents. Using a copper/chiral phosphoramidite complex together with a Lewis acid (BF(3)·OEt(2)), full selectivity for the anti isomer and excellent enantioselectivities were obtained for the ring opened products. 相似文献
242.
Mary F. Wang Alena N. Joignant Alexandria L. Sohn Kenneth P. Garrard David C. Muddiman 《Journal of mass spectrometry : JMS》2023,58(3):e4911
The field of mass spectrometry imaging (MSI) is constantly evolving to analyze a diverse array of biological systems. A common goal is the need to resolve cellular and subcellular heterogeneity with high spatial resolution. As the field continues to progress towards high spatial resolution, other parameters must be considered when developing a practical method. Here, we discuss the impacts of high spatial resolution on the time of acquisition and the associated implications they have on an MSI analysis (e.g., area of the region of interest). This work presents a brief tutorial serving to evaluate high spatial resolution MSI relative to time of acquisition and data file size. 相似文献
243.
Alena Budinská Prof. Helma Wennemers 《Angewandte Chemie (International ed. in English)》2023,62(17):e202300537
Trifluoromethylsulfones (triflones) are useful compounds for synthesis and beyond. Yet, methods to access chiral triflones are scarce. Here, we present a mild and efficient organocatalytic method for the stereoselective synthesis of chiral triflones using α-aryl vinyl triflones, building blocks previously unexplored in asymmetric synthesis. The peptide-catalyzed reaction gives rise to a broad range of γ-triflylaldehydes with two non-adjacent stereogenic centers in high yields and stereoselectivities. A catalyst-controlled stereoselective protonation following a C−C bond formation is key to control over the absolute and relative configuration. Straightforward derivatization of the products into, e.g., disubstituted δ-sultones, γ-lactones, and pyrrolidine heterocycles highlights the synthetic versatility of the products. 相似文献