A new type of ferrocenyl P,P,N,N,O-ligand has been developed through a one-step transformation. This represents a rare example of a ligand containing both chiral bisphosphine and diamine groups suitable for ruthenium-catalyzed asymmetric hydrogenation. Its ruthenium complex can be directly prepared by stirring the ligand and [Ru(benzene)Cl] at 90 °C in DMF for 4 hours. The catalyst showed high reactivity and enantioselectivity in the hydrogenation (AH) of simple ketones and α,β-unsaturated ketones, providing the corresponding chiral aryl alkyl alcohols and chiral allyl alcohols with up to 99% yield and 96% ee.
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http://dx.doi.org/10.1039/d4ob01679c | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
The homogeneous catalytic hydrogenation of benzo-fused heteroarenes generally provides partially hydrogenated products wherein the heteroaryl ring is preferentially reduced, such as quinoline hydrogenation, leading to 1,2,3,4-tetrahydroquinoline. Herein, we report a carbocycle-selective hydrogenation of fused -heteroarenes (quinoline, isoquinoline, quinoxaline, etc.) using the Ru complex of a chiral spiroketal-based diphosphine (SKP) as the catalyst, affording the corresponding 5,6,7,8-tetrahydro products in high chemoselectivities.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Department of Chemistry, and Medi-Pingshan, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen 518055, China.
A new type of ferrocenyl P,P,N,N,O-ligand has been developed through a one-step transformation. This represents a rare example of a ligand containing both chiral bisphosphine and diamine groups suitable for ruthenium-catalyzed asymmetric hydrogenation. Its ruthenium complex can be directly prepared by stirring the ligand and [Ru(benzene)Cl] at 90 °C in DMF for 4 hours.
View Article and Find Full Text PDFJ Am Chem Soc
September 2024
Department of Chemistry, University of Texas at Austin, 105 E 24th St., Austin, Texas 78712, United States.
The first total synthesis of the pentacyclic phenylnaphthacenoid type II polyketide antibiotic formicamycin H is described. A key feature of the synthesis involves the convergent, regioselective assembly of the tetracyclic core via ruthenium-catalyzed α-ketol-benzocyclobutenone [4 + 2] cycloaddition. Double dehydration of the diol-containing cycloadduct provides an achiral enone, which upon asymmetric nucleophilic epoxidation and further manipulations delivers the penultimate tetracyclic trichloride in enantiomerically enriched form.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
Instituto Investigaciones Químicas (CSIC-US), Centro de Innovación en Química Avanzada (ORFEO-CINQA), C/ Américo Vespucio 49, 41092, Sevilla, Spain.
A ruthenium-catalyzed reductive amination via asymmetric transfer hydrogenation (ATH) has been used to perform an efficient dynamic kinetic resolution (DKR) of N-aryl 2-formyl pyrroles decorated with a phosphine moiety positioned at the ortho' position. The strategy relies on the labilization of the stereogenic axis in the substrate facilitated by a transient Lewis acid-base interaction (LABI) between the carbonyl carbon and the phosphorus center. The reaction features broad substrate scope of aliphatic amines and N-aryl pyrrole scaffolds, and proceeds under very mild conditions to afford P,N atropisomers in good to high yields and excellent enantioselectivities (up to 99 % ee) for both diphenyl and dicyclohexylphosphino derivatives.
View Article and Find Full Text PDFOrg Lett
June 2024
Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.
Tractable and commercially available esters (and amides) of β-hydroxypropionic acid serve as malonic semialdehyde proelectrophiles in enantioselective ruthenium-catalyzed hydrogen autotransfer crotylations mediated by butadiene. Through iterative asymmetric butadiene-mediated crotylations of ethyl 3-hydroxypropanoate, total syntheses of the polyketide natural products octalactin A and B were achieved in fewer steps than previously possible.
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