[reaction: see text] The Cu(I)-catalyzed cycloisomerization of tertiary 5-en-1-yn-3-ols with an 1,2-alkyl shift affords stereoselectively tri- and tetracyclic compounds of high molecular complexity. These results are in agreement with a mechanism in which the cyclopropanation precedes the rearrangement.
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http://dx.doi.org/10.1021/ol0603864 | DOI Listing |
Org Lett
September 2024
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, People's Republic of China.
Numerous effective bioisosteric replacements have been identified through substituting scaffolds and functional groups in lead molecules with alternative ones that preserve or enhance the desired biological activity of the original compound. Here, a copper-catalyzed nucleophilic cycloisomerization was developed to access potential bioisosteric replacements of azepinoindole. In this process, "tetra-alkene" characteristic of indolizine undergoes a 12π electrocyclization, offering a complementary method to obtain azepinoindolizine derivatives that are otherwise challenging to prepare through conventional means.
View Article and Find Full Text PDFOrg Lett
May 2024
Key Laboratory of Chemical Biology of Fujian Province and State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Catalytic cyclization of enynes is an efficient approach for the preparation of cyclic compounds, and a large variety of four- to six-membered rings could be synthesized using this method. However, it has been rarely employed for the construction of medium- and large-sized rings. Herein, we describe a copper-catalyzed cycloisomerization of ene-ynamides through a [2 + 2] cyclization/electrocyclic ring opening cascade, leading to the atom-economical assembly of indole-fused medium- and large-sized rings in moderate to excellent yields under mild reaction conditions.
View Article and Find Full Text PDFNat Commun
January 2022
School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China.
The construction of axially chiral N-heterobiaryls is of great interest as a result of their occurrence in organocatalysts, chiral ligands, natural products, and biologically active molecules. Despite remarkable achievements in this area, strategies for the preparation of new classes of axially chiral N-heterobiaryls remain to be further explored. Herein, we report the enantioselective synthesis of axially chiral arylquinolizones through an intramolecular atroposelective cycloisomerization.
View Article and Find Full Text PDFOrg Lett
May 2021
Institut fur Organische Chemie, Albert-Ludwigs-Universitat Freiburg Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.
A novel copper-catalyzed cycloisomerization of unactivated allene-tethered propargyl oximes has been developed for the synthesis of hexahydropyrrolo[3,4-]azepin-5(4)-ones. This one-pot domino reaction proceeds via a [2,3]-sigmatropic rearrangement, a [3 + 2] cycloaddition, and another [3,3]-sigmatropic rearrangement. The methodology offers a practical and straightforward route for the rapid assembly of both ring components of the fused bicyclic motifs from acyclic precursors by simultaneously forming four new bonds (a C═O, a C═N, and two C-C bonds) in a single step.
View Article and Find Full Text PDFRSC Adv
October 2020
CCNU-uOttawa Joint Research Centre, Key Laboratory of Pesticides & Chemical Biology Ministry of Education, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
A highly enantioselective copper-catalyzed propargylic amination starting from benzylic allylic amines has been developed with a new chiral N,N,P ligand. A series of -tethered 1,6-enynes were synthesized in good to excellent yields with excellent enantioselectivities. Utilization of transition metal-catalyzed cycloisomerization of 1,6-enynes provides several enantioselectively enriched chiral five-membered N-heterocycles efficiently.
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