The highly enantioselective hydrogenation of quinoline derivatives is developed using [Ir(COD)Cl]2/(R)-MeO-Biphep/I2 system, and this methodology has been applied to the asymmetric synthesis of three naturally occurring alkaloids angustureine, galipinine, and cuspareine. This method provided an efficient access to a variety of optically active tetrahydroquinolines with up to 96% ee.
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http://dx.doi.org/10.1021/ja0353762 | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Here, we report the enantioselective total syntheses of four diepoxy--kaurane diterpenoids including (-)-Macrocalin B, (-)-Acetyl-macrocalin B, and (-)-Isoadenolin A and the revised structure of (-)-Phyllostacin I, which hinges on the strategic design of a regioselective and stereospecific trapping of a highly reactive [3.2.1]-bridgehead enone intermediate via a tethered intramolecular Diels-Alder reaction.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
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.
Catalytic asymmetric transformation of donor-acceptor cyclopropanes (DACs) has been proven to be a highly valuable and robust strategy to construct diverse types of enantioenriched molecules. However, the use of 1,1,2,2-tetrasubstituted DACs to form products bearing quaternary stereocenters remains a long-term unsolved challenge. Here, we report the copper-catalyzed asymmetric aminative ring opening of tetrasubstituted alkynyl DACs that delivers a myriad of α-tertiary amines with high levels of enantioselectivities.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Chemistry, Indian Institute of Technology Jammu, Jagti, NH-44, Nagrota Bypass, Jammu 181221, J&K, India.
A highly regio-, enantio- and diastereo-selective strategy involving initial enantioselective conjugate addition to 4-nitro-5-styrylisoxazoles serves as a key step for the desymmetrization of 2,5-cyclohexadienones has been disclosed. We have designed a new class of 2,5-cyclohexadienones appended with 4-nitro-5-styrylisoxazoles to undergo organocatalytic asymmetric double or triple conjugate addition in a domino sequence depending on the substrate type leading to desymmetrization of the 2,5-cyclohexadienone core. The developed protocol allows the construction of a valuable hydrophenanthrene core or a unique bridged scaffold bearing multiple chiral centers with excellent enantio- (up to >99.
View Article and Find Full Text PDFChem Sci
December 2024
Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
Development of chiral organic materials with a strong chiroptical response is crucial to advance technologies based on circularly polarized luminescence, enantioselective sensing, or unique optical signatures in anti-counterfeiting. The progress in the field is hampered by the lack of structure-property relationships that would help designing new chiral molecules. Here, we address this challenge by synthesis and investigation of two chiral macrocycles that integrate in their structure a pseudo-meta [2.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Frontiers Science Center for New Organic Matter, Tianjin 300071, China.
The development of effective synthetic methods to construct γ-lactams bearing a chiral α-quaternary carbon from relatively inert C(O)-H bonds with alkenes has been an elusive challenge. Herein, we used a naphthylamine-derived phosphine oxide ligating Ni and Al bimetallic catalyst to realize a carbonylative cyclization of formyl C-H bonds with alkenes, highly regio- and enantioselectively constructing γ-lactams bearing a chiral α-quaternary carbon in up to 99% yield and 98% ee. These γ-lactams proved to be versatile synthetic precursors for many biologically active molecules.
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