[reaction: see text] [2.2]Paracyclophane-based ketimine ligands were evaluated as catalysts for the enantioselective addition of in situ-prepared alkynylzinc reagents to aldehydes. The initial high activity and enantioselectivity of these ligands could be improved by an additive screening. The final protocol gives chiral propargyl alcohols in up to >98% ee.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/ol049596b | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Shandong University, Department of Chemistry, 27 South Shanda Road, 250100, Jinan, CHINA.
Planar chirality found tremendous use in many fields, such as chemistry, optics, and materials science. In particular, planar chiral [2.2]paracyclophanes (PCPs) are a type of structurally interesting and practically useful chiral compounds bearing unique electronic and photophysical properties and thus have been widely used in π-stacking polymers, organic luminescent materials, and as a valuable toolbox for developing chiral ligands or organocatalysts.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Institute of Research on the Structure of Matter, University of Chinese Academy of Sciences, Fuzhou 350100, China.
Adv Sci (Weinh)
January 2025
School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Chiral fully-substituted allenes are synthetically significant and pivotal building blocks that can engage in diverse transformations toward a variety of bioactive molecules. The enantioselective assembly of these skeletons using readily available reactants offers significant advantages but remains challenging. Herein, an asymmetric formal Michael-type addition of alkynyl imines with the key alkylgold intermediates derived in situ from N-propargylamides is accomplished under gold-complex and chiral quinine-derived squaramide (QN-SQA) synergetic catalysis.
View Article and Find Full Text PDFOrg Lett
November 2024
Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France.
The tethered counterion-directed catalysis (TCDC) strategy enables the Au(I)-catalyzed highly enantioselective synthesis of bicyclic furan derivatives via a reaction sequence combining the cycloisomerization of 2-alkynyl enones and the addition of nucleophiles. A large range of oxygenated nucleophiles, such as water, alcohols, carboxylic acids, and peroxides, have successfully been used as nucleophiles, delivering the chiral furane derivatives in high enantioselectivities (mostly above 90% enantiomeric excess). The CPAphosAuCl complexes were used with catalytic loadings as low as 0.
View Article and Find Full Text PDFInt J Mol Sci
September 2024
Natural Compounds and Organic Synthesis Laboratory, Migal-Galilee Research Institute, Kiryat Shmona 11016, Israel.
Chiral pincer complexes, characterized by their rigid tridentate coordination framework, have emerged as powerful catalysts in asymmetric synthesis. This review provides a comprehensive overview of recent advancements in the development of chiral pincer-type ligands and their corresponding transition metal complexes. We highlight the latest progress in their application across a range of catalytic asymmetric reactions, including the (transfer) hydrogenation of polar and non-polar bonds, hydrophosphination, alkynylation, Friedel-Crafts reactions, enantioselective reductive cyclization of alkynyl-tethered cyclohexadienones, enantioselective hydrosilylation, as well as Aza-Morita-Baylis-Hillman reactions.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!