Highly enantioselective rhodium-catalyzed addition of arylboroxines to N-unprotected ketimines is realized for the first time by employing chiral BIBOP-type ligands with a Rh loading as low as 1 mol %. A range of chiral α-trifluoromethyl-α,α-diaryl α-tertiary amines or 3-amino-3-aryloxindoles were formed with excellent ee values and yields by employing either WingPhos or PFBO-BIBOP as the ligand. The method has enabled an efficient enantioselective synthesis of cipargamin.
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http://dx.doi.org/10.1002/anie.201910008 | DOI Listing |
Org Lett
January 2025
Department of Chemistry, School of Science, China Pharmaceutical University, Nanjing 211198, People's Republic of China.
The development and enantioselective synthesis of two types of -symmetric spirobi[dihydrophenalene] structures is reported. The reaction proceeds via rhodium-catalyzed 2-fold asymmetric conjugate arylation of dienones followed by BF·OEt-promoted spirocyclization to give the enantiopure spiro products. Additive-dependent chemodivergent synthesis of 3,3'-diarylated 2,2',3,3'-tetrahydro-1,1'-spirobi[phenalene]-9,9'-diols (3,3'-Ar-SPHENOLs) and the corresponding spiro diary ethers from the same intermediate is achieved.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Shanghai Inst Org Chem, State Key Lab Organometallic Chem, 345 Lingling Lu, 200032, Shanghai, CHINA.
Rhodium-catalyzed regio- and enantioselective allylic arylation of racemic alkyl- and aryl- substituted allylic carbonates with arylboronic acids using commercially available BIBOP ligand is reported. This reaction proceeds at room temperature without base or other additive to deliver allylic arylation products in excellent yields, regio- and enantioselectivity (up to 95% yield, >20:1 b/l, >99% ee). Rh/BIBOP is disclosed as an efficient catalytic system for allylic substitution reaction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Tsinghua University, Department of Chemistry, 1 Tsinghua Yuan, 100084, Beijing, CHINA.
Enantioselective hydrogenation of tetrasubstituted alkenes to form 1,2-contiguous stereocenters is a particularly appealing but highly challenging transformation in asymmetric catalysis. Despite the notable progress achieved in enantioselective hydrogenation over the past decades, enantioselective hydrogenation of all-carbon tetrasubstituted alkenes containing multiple alkyl groups remains an unsolved challenge. Here, we report a rhodium-catalyzed highly diastereo- and enantioselective hydrogenation of diverse acyclic multisubstituted alkenes under mild conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States.
The utilization of β-fluoroamines as pharmaceutical components for drug development has attracted a considerable amount of interest. However, direct access to tertiary β-fluoroamines is challenging. We herein report the rhodium-catalyzed asymmetric amination of tertiary allylic trichloroacetimidates with anilines and cyclic aliphatic amines to access tertiary β-fluoroamines, where the α-carbon atom is bonded to four different substituents, in good yield with high levels of enantioselectivity.
View Article and Find Full Text PDFChemistry
December 2024
Department of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria.
We present a comprehensive account on the evolution of a synthetic platform for a subfamily of ent-pimaranes. For the most complex member, norflickinflimiod C, five distinct strategies relying on either cationic or radical polyene cyclizations to construct the requisite tricyclic carbon scaffold were explored. Insights from early and late stage oxidative and reductive dearomatization studies ultimately led to a mild, rhodium-catalyzed arene hydrogenation for the final synthetic route.
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