In this paper is described a synthesis of enantiomerically enriched, configurationally stable organozinc reagents by catalytic enantioselective carbozincation of a vinylboronic ester. This process furnishes enantiomerically enriched α-borylzinc intermediates that are shown to undergo stereospecific reactions, producing enantioenriched secondary boronic ester products. The properties of the intermediate α-borylzinc reagent are probed and the synthetic utility of the products is demonstrated by application to the synthesis of (-)-aphanorphine and (-)-enterolactone.
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http://dx.doi.org/10.1021/jacs.1c05274 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
Regiodivergent asymmetric synthesis represents a transformative strategy for the efficient generation of structurally diverse chiral products from a single set of starting materials, significantly enriching their enantiomeric composition. However, the design of radical-mediated regiodivergent and enantioselective reactions that can accommodate a wide range of functional groups and substrates has posed significant challenges. The obstacles primarily lie in switching the regioselectivity and achieving high enantiodiscrimination, especially when dealing with high-energy intermediates.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia.
Cyclopropanols have attracted significant attention in organic synthesis as versatile three-carbon synthons, as this readily available class of donor-activated cyclopropanes undergoes miscellaneous transformations, either ring-opening or with retention of the cyclopropane ring. This review summarizes stereoselective and stereoretentive transformations suitable for asymmetric synthesis. The utility of cyclopropanols is discussed for two main strategies: (i) substrate-controlled transformations using enantiomerically enriched cyclopropanol intermediates through a traditional approach, and (ii) the use of nonchiral or racemic cyclopropanols, where asymmetric induction is achieved through a chiral catalyst, representing a direction that has recently emerged.
View Article and Find Full Text PDFNanoscale
December 2024
Université de Strasbourg, CNRS, CMC UMR 7140, F-67000 Strasbourg, France.
Nanosized chiral octahedral M coordination cages were prepared self-assembly of sulfonylcalix[4]arene tetranuclear M(II) clusters (M = Co or Ni) with enantiomerically enriched linkers based on tris(dipyrrinato)cobalt(III) complexes, appended with peripheral carboxylic groups. Two pairs of enantiomers of cages were obtained and unambiguously characterized from a structural point of view, using single crystal X-ray diffraction. Chiral-HPLC was used to evidence the enantiomers.
View Article and Find Full Text PDFAmino Acids
December 2024
Scientific and Production Center "Armbiotechnology" of NAS RA, 14 Gyurjyan Str, 0056, Yerevan, Armenia.
A synthesis of new enantiomerically enriched derivatives of (S)-α-aminopropionic acid, containing in the β-position 1,2,3-triazole groups coupled with a o-, m- and p-substituted phenyl residue, was developed based on Cu(I) catalyzed [3 + 2] cycloaddition of azides with alkynes. As the starting materials was used the square-planar Ni(II)complex of the Schiff base of propargylglycine with the chiral auxiliary BPB (Benzylprolylbenzophenone) and 1,4-substituted phenyl azides. The assignment of the (S)-absolute configuration of the α-carbon atom of the amino acid residue of the main diastereomeric complexes of the cycloaddition products was carried out on the basis of positive Cotton effects in the region of 480-580 nm of the circular dichroism spectra.
View Article and Find Full Text PDFNat Chem
November 2024
Department of Chemistry, Northeast Normal University, Changchun, China.
Heterocycle skeletal editing has recently emerged as a powerful tactic for achieving heterocycle-to-heterocycle transmutation without the need for multistep de novo heterocycle synthesis. However, the enantioselective skeletal editing of heteroarenes through single-atom logic remains challenging. Here we report the enantiodivergent dearomative skeletal editing of indoles and pyrroles via an asymmetric carbon-atom insertion, using trifluoromethyl N-triftosylhydrazones as carbene precursors.
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