An efficient rhodium-catalyzed enantioselective arylation of isatin-derived -Boc ketimines with arylboroxines has been developed using H-BINOL-derived phosphite-olefin as a chiral ligand. This method allows access to a broad variety of valuable tetrasubstituted 3-amino-2-oxindole derivatives in good yields (up to 98%) with excellent enantioselectivities (up to 98% ee).
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http://dx.doi.org/10.1021/acs.orglett.9b02787 | DOI Listing |
Chemistry
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.
View Article and Find Full Text PDFOrg Lett
December 2024
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, P. R. China.
Catalytic hydrosilylation of 1,1-disubstituted enamides is one of the most challenging and synthetically useful processes in organosilicon chemistry and asymmetric catalysis. Herein, we report a rhodium-catalyzed enantioselective hydrosilylation of α-arylenamides with substituted hydrosilanes with the aid of chiral P-ligand, including newly developed spirophosphite ligands, giving various chiral β-silylated amides in excellent yields with good to excellent enantioselectivities (98:2 er after recrystallization). In addition, chiral β-silylated amines can be obtained by further functionalization of the hydrosilylation product.
View Article and Find Full Text PDFJ 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 PDFSci Adv
November 2024
Institute of Chemistry Frontier, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China.
A pair of enantiomers is known to have different biological activities. Two catalysts with opposite chirality are nearly always required to deliver both enantiomeric products. In this work, chiral rhodium(III) cyclopentadienyl complexes are repurposed as efficient catalysts for enantiodivergent and atroposelective hydroamination of sterically hindered alkynes.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Shanghai 200032, China.
Chiral γ-amino alcohols are prevalent structural motifs in natural products and bioactive compounds. Nevertheless, efficient and atom-economical synthetic methods toward enantiomerically enriched γ-amino alcohols are still lacking. In this study, a highly enantioselective rhodium-catalyzed reductive hydroformylation of readily available α-substituted enamides is developed, providing a series of pharmaceutically valuable chiral 1,3-amino alcohols in good yields and excellent enantioselectivities in a single step.
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