A very fast reaction and enantioselectivities >98% have been reached in the rhodium-catalyzed arylboronic acid addition to enones using a monodentate phosphoramidite ligand. Temperature-dependent studies show that monodentate phosphoramidites form stable complexes with metals and can induce high enantioselectivities even at high temperatures in polar solvents.
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http://dx.doi.org/10.1021/jo035155e | DOI Listing |
Chemistry
November 2022
Key Laboratory of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.
Palladium-catalyzed enantioselective cyclization of enynes has contributed significantly to the construction of chiral cyclic molecules. In contrast, the catalytic asymmetric cyclization involving halopalladation remains an unresolved challenge with the inevitable disturbance of the halide ions. Herein, an intramolecular chlorine transfer strategy is used to accomplish the enantioselective chloropalladation cyclization of 1,6-enynes.
View Article and Find Full Text PDFChemistry
June 2022
Department of Applied Chemistry, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1-H113 Ookayama, Meguro-ku, Tokyo, 152-8552, Japan.
Optically active cyclopropanes have been widely investigated especially from the views of pharmaceutical and agrochemical industries, and substituting one of the methylenes with the difluoromethylene unit should be promising for developing novel biologically relevant compounds and functional materials. In this paper, the copper-catalyzed enantioselective hydrosilylation of gem-difluorocyclopropenes to provide the corresponding chiral gem-difluorocyclopropanes is presented. The use of copper(I) chloride, chiral ligands including bidentate BINAPs and monodentate phosphoramidites, and silylborane Me PhSi-Bpin accompanying sodium tert-butoxide in methanol was appropriate for the enantioselective hydrosilylation of the strained C=C double bond, and the resultant chiral difluorinated three-membered ring was unambiguously characterized.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2021
Key Laboratory of Synthetic and Nature Molecule Chemistry of Ministry of Education, Department of Chemistry & Materials Science, Northwest University, Xi'an, 710127, P. R. China.
Asymmetric hydroxycarbonylation is one of the most fundamental yet challenging methods for the synthesis of carboxylic acids. Herein, we reported the development of a palladium-catalyzed highly enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water. A monodentate phosphoramidite ligand L6 plays vital role in the reaction.
View Article and Find Full Text PDFJ Am Chem Soc
March 2021
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
The catalytic asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides with various electron-deficient alkenes provide the most straightforward protocol for the preparation of enantioenriched pyrrolidines in organic synthesis. However, the employment of conjugated alkenyl heteroarenes as dipolarophiles in such protocols to afford a class of particularly important molecules in medicinal chemistry is still a great challenge. Herein, we report that various β-substituted alkenyl heteroarenes, challenging internal alkene substrates without a strong electron-withdrawing substituent, were successfully employed as dipolarophiles for the first time in the Cu(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides.
View Article and Find Full Text PDFJ Am Chem Soc
January 2021
Key Laboratory of Synthetic and Nature Molecule of Ministry of Education, Department of Chemistry & Materials Science, Northwest University, Xi'an 710127, P.R. China.
A palladium-catalyzed asymmetric Markovnikov hydroaminocarbonylation of alkenes with anilines has been developed for the atom-economical synthesis of 2-substituted propanamides bearing an α-stereocenter. A novel phosphoramidite ligand was discovered which exhibited very high reactivity and selectivity in the reaction. This asymmetric Markovnikov hydroaminocarbonylation employs readily available starting materials and tolerates a wide range of functional groups, thus providing a facile and straightforward method for the regio- and enantioselective synthesis of 2-substituted propanamides under ambient conditions.
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