A mild method for the facile removal of phosphine oxide from the crude products of Wittig and Appel reactions is described. Work-up with oxalyl chloride to generate insoluble chlorophosphonium salt (CPS) yields phosphorus-free products for a wide variety of these reactions. The CPS product can be further converted into phosphine.
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http://dx.doi.org/10.1039/c2ob07074j | DOI Listing |
J Am Chem Soc
December 2024
Department of Chemistry and Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei 106319, Taiwan (R.O.C.).
Reactive carbonyl species (RCS) are important biomarkers of oxidative stress-related diseases because of their highly reactive electrophilic nature. Despite their potential as triggers for prodrug activation, selective labeling approaches for RCS remain limited. Here, we utilized triphenylphosphonium groups to chemoselectively capture RCS via an aqueous Wittig reaction, forming α,β-unsaturated carbonyls that enable further functionalization.
View Article and Find Full Text PDFChemistry
January 2025
Department of Chemistry, BITS-Pilani, Hyderabad Campus, Jawahar Nagar, Shamirpet, Hyderabad, 500078, India.
Oxidative dephosphorylation reactions usually generate symmetrically substituted alkenes from organophosphonates. Even the ubiquitous presence of oxygen can produce such alkenes inadvertently as a side product in small amounts from Wittig/Horner-Wadsworth-Emmons (HWE) reactions. So far, aldehydes have been expected to be the on-pathway intermediate since their discovery, but there was no substantial experimental evidence to support this.
View Article and Find Full Text PDFThe first search for soft unclustered energy patterns (SUEPs) is performed using an integrated luminosity of 138 fb^{-1} of proton-proton collision data at sqrt[s]=13 TeV, collected in 2016-2018 by the CMS detector at the LHC. Such SUEPs are predicted by hidden valley models with a new, confining force with a large 't Hooft coupling. In events with boosted topologies, selected by high-threshold hadronic triggers, the multiplicity and sphericity of clustered tracks are used to reject the background from standard model quantum chromodynamics.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, 450001, Zhengzhou, Henan Province, P.R. China.
In the present study, the mechanism, origin of chemoselectivity, and substituent effects of the phosphine-catalyzed ring-opening reaction of cyclopropyl ketone have been investigated using the DFT method. Multiple pathways, including the formation of hydrofluorenone, the Cloke-Wilson product, and cyclopenta-fused product, were studied and compared. The computational results show that the pathway for the formation of hydrofluorenone is the most favorable one, which involves four processes: nucleophilic substitution to open the three-membered ring, an intramolecular Michael addition for the formation of an enolate intermediate, an intramolecular [1,5]-proton transfer to give ylide, and an intramolecular Wittig reaction to deliver the final product.
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