The external chiral ligand-controlled asymmetric conjugate addition reaction of lithium amides with alpha,beta-unsaturated esters provided beta-amino esters in high yields and high enantioselectivities.
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Ligand-controlled regiodivergent arylation of aryl(alkyl)alkynes and asymmetric synthesis of axially chiral 9-alkylidene-9,10-dihydroanthracenes.
Nat Commun
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Inner Mongolia Key Laboratory of Fine Organic Synthesis, Inner Mongolia University, 235 West University Street, Hohhot, 010021, China.
Article Synopsis
- The study demonstrates that the addition of arylboronic acids to aryl(alkyl)alkynes can preferentially form 1,1-diarylalkenes (α-addition) when using a rhodium catalyst with a chiral diene ligand.
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Ligand-Controlled Regiodivergent Ring Expansion of Benzosilacyclobutenes with Alkynes Route to Axially Chiral Silacyclohexenyl Arenes.
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Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
A ligand-controlled regiodivergent and enantioselective ring expansion of benzosilacyclobutenes with internal naphthyl alkynes has been achieved by adjusting the ligand cavity size. The ligand ()-8-binaphthyl phosphoramidite, featuring small methyl groups on its arms, provides a spacious cavity that favors sterically demanding Si-Csp ring expansion, predominantly yielding axially chiral ()-1-silacyclohexenyl arenes. In contrast, the ligand ()-spiro phosphoramidite, with bulky -Bu groups on its arms, offers a compact cavity that facilitates less sterically demanding Si-Csp ring expansion, leading primarily to axially chiral ()-2-silacyclohexenyl arenes.
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J Am Chem Soc
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Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang Province 310030, China.
Owing to substantial advances in the past several decades, transition-metal-catalyzed asymmetric reactions have garnered considerable attention as pivotal methods for constructing chiral molecules from abundant, readily available achiral counterparts. These advances are largely attributed to the development of chiral ligands that control stereochemistry through steric repulsion and other noncovalent interactions between the ligands and functional groups or prochiral centers on the substrates. However, stereocontrol weakens dramatically with increasing distance between the reaction site and the functional group or prochiral center.
View Article and Find Full Text PDFLigand-Controlled Enantioselective and Regiodivergent Construction of 1,2- and 1,3-Disubstituted Alicycles.
Org Lett
September 2024
Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, Guangdong 528400, People's Republic of China.
Three-dimensional alicyclic skeletons with multiple stereochemically defined chiral centers are highly valuable in modern drug discovery. Here, we reported a diverse approach to access 1,2- and 1,3-disubstituted chiral cycloalkanes by the strategy of NiH-catalyzed, transannular-directed alkene desymmetrization. The ring strain of the bridged bicyclic organonickel intermediate and the coordination effect of the ligand were identified as crucial factors in determining site selectivity by influencing the NiH migration step.
View Article and Find Full Text PDFStereodivergent access to non-natural α-amino acids via enantio- and /-selective catalysis.
Science
August 2024
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
The precise control of and configurations of the carbon-carbon double bond in alkene synthesis has long been a fundamental challenge in synthetic chemistry, even more pronounced when simultaneously striving to achieve enantioselectivity [(,), (,), (,), (,)]. Moreover, enantiopure non-natural α-amino acids are highly sought after in organic and medicinal chemistry. In this study, we report a ligand-controlled stereodivergent synthesis of non-natural α-quaternary amino acids bearing trisubstituted alkene moieties in high yields with excellent enantioselectivity and / selectivities.
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