The stereoselective synthesis of P-chirogenic phosphines bearing an o-hydroxyalkyl chelating arm is described. The synthesis is based either on the hydroxyalkylation of P-chirogenic o-bromophenylphosphines (borane) or on their carbonatation and then reduction. The hydroxyalkylation with benzaldehyde or pivalaldehyde affords a mixture of epimers which are isolated by chromatography and characterized by their X-ray structures. Preliminary assays of free P-chirogenic o-(hydroxyalkyl)phenyl phosphines, as new functional Lewis bases in catalyzed asymmetric aza-MBH reaction, lead to β-aminoester derivatives with ee values up to 74%.
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http://dx.doi.org/10.1021/ol400515e | DOI Listing |
J Org Chem
December 2024
Université de Bourgogne, UFR des Sciences et Techniques, ICMUB UMR-CNRS 6302, BP 47870, 21078 Dijon Cedex, France.
Chiral diphosphines with a biphenyl bridge and the chirality borne by the phosphorus atoms and not due to the atropoisomery of the biaryl backbone have been scarcely studied. Herein, we report the asymmetric synthesis of the (,)-2,2'-bis(ferrocenylphenylphosphino)biphenyl (BipheP*) ligand and its application in Rh-catalyzed hydrogenation. The synthesis was based on the enantioselective preparation of P-chirogenic ferrocenyl(-bromophenyl)phenylphosphine by the reaction of -phosphine-borane with 1,2-dibromobenzene and its homocoupling into BipheP*.
View Article and Find Full Text PDFJ Org Chem
December 2023
Université de Bourgogne-Franche-Comté-Institut de Chimie Moléculaire (ICMUB-OCS, UMR-CNRS 6302), BP 47870, 21078 Dijon Cedex, France.
In the recent past, the chirality borne by a phosphorus center has aroused growing interest in many fields, and the development of new methodologies, notably using inexpensive reagents and simple experimental conditions, has become topical. An efficient stereoselective synthesis of P-chirogenic phosphinites useful as chiral phosphorus building blocks is herein described thanks to a new intramolecular phosphorus rearrangement based on P*(III)-phosphinyl N→O migration. This rearrangement was performed by heating at 50 °C aminophosphine-boranes, easily prepared from chiral amino alcohols, with DABCO in toluene overnight.
View Article and Find Full Text PDFJ Am Chem Soc
June 2022
Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan.
A new series of -symmetric P-chirogenic bisphosphine ligands of the type ()-5,8--Quinox-Bu (Silyl = SiMe, SiEt, SiMePh) have been developed. The bulky silyl modulators attached to the ligand backbone fix the phosphine substituents to form rigid chiral environments that can be used for substrate recognition. The ligand showed high performances for a copper(I)-catalyzed asymmetric borylative cyclopropanation of bulky silyl-substituted allylic electrophiles to afford higher disfavored 1,2--silyl-boryl-cyclopropanes than the other possible isomers, -cyclopropane and allylboronate (up to 97% yield; 98% ee; / = >99:1; cyclopropane/allylboronate = >99:1).
View Article and Find Full Text PDFiScience
May 2022
Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA.
Chemical agents that specifically exploit metabolic vulnerabilities of cancer cells will be beneficial but are rare. The role of oxidative phosphorylation (OXPHOS) in promoting and maintaining triple-negative breast cancer (TNBC) growth provides new treatment opportunity. In this work, we describe AuPhos-19, a small-molecule gold(III)-based agent bearing a chiral phosphine ligand that selectively disrupts mitochondrial metabolism in murine and human TNBC cells but not normal epithelial cells.
View Article and Find Full Text PDFChemistryOpen
November 2022
Department of Chemistry and Biomolecular Science Faculty of Engineering, Gifu University Yanagido, Gifu, 501-1193, Japan.
The substitution reaction of phosphinates with a binaphthyloxy group at the phosphorus atom with lithium alkoxides proceeded with good to high efficiencies to give P-chirogenic phosphinates with a high enantiomeric ratio. As alcohols, primary, secondary, and tertiary alcohols could be used, and the use of tert-butyl alcohol yielded the products with a higher enantiomeric ratio. A substrate with two different alkyl groups on the phosphorus atom could also participate in the substitution reaction to give the corresponding products in good yields with excellent selectivity.
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