The Lewis acid-promoted addition of 1,3-bis(silyl)propenes to aldehydes to provide the corresponding (E)-1,3-dienes in excellent stereoselectivity and good to excellent yields is reported. The procedure is mild, base-free, and operationally straightforward.
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http://dx.doi.org/10.1021/jo2013466 | DOI Listing |
Chem Commun (Camb)
December 2024
Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, Julián Clavería 8, 33006-Oviedo, Spain.
Cyclopropanes are commonly used as valuable 3-carbon building blocks. Herein, we disclose a different reactivity pattern of furanyl cyclopropanes, which serve as a 4-carbon component in Lewis acid-promoted [4+2] cycloadditions with nitrosoarenes to afford 1,2-oxazine derivatives. Importantly, the regioselectivity of the cycloaddition reaction can be controlled by the appropriate choice of the Lewis acid.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States.
The synthesis of 1-azido -nucleosides is described to expand the set of azide-functionalized nucleosides for bioorthogonal applications and as potential antiviral drugs. Lewis acid-promoted azidation of a nucleoside hemiketal resulted in the formation of a tetrazole through a Schmidt reaction manifold. Conformational control to prevent ring-chain tautomerism enabled efficient 1-azidation with complete β-diastereoselectivity.
View Article and Find Full Text PDFJ Org Chem
December 2024
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. China.
A simple and effective strategy for the construction of disulfide-substituted oxazole derivatives from amides, ynals, and acetyl disulfides via a Lewis acid-promoted three-component reaction has been reported. In addition, this reaction possesses other unique advantages, such as transition-metal-free catalysis, the production of disulfides, good functional group tolerance, and good regioselectivity.
View Article and Find Full Text PDFOrg Lett
November 2024
Applied Chemistry and Chemical Engineering, Graduate School of Engineering, Kogakuin University, Nakano 2665-1, Hachioji, Tokyo 192-0015, Japan.
Hexahydro-2-cyclopenta[]furan fused to electron-rich aromatic rings reacts with various aromatic aldehydes in different modes to build diverse frameworks. The reaction of a dimethoxybenzene-fused cyclopentafuran generated diquinanes fused with a hydrofuran ring, indenopyrans, or diarylindanes depending upon the type of aromatic aldehydes, whereas an indole-annulated cyclopentafuran generated another type of diquinane fused with hydrofuran ring or benzylidenecyclopentafuran. The chemodivergence is due to the different properties between indole- and dimethoxybenzene-fused hydrocyclopentafurans.
View Article and Find Full Text PDFOrg Lett
September 2024
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, People's Republic of China.
A visible-light-induced intramolecular diradical-mediated hydrogen atom transfer (DHAT) of primary, secondary, and tertiary C(sp)-H bonds and subsequent cyclization is described. This transformation is enabled by triplet energy transfer upon Lewis acid coordination to alkyl-substituted arylvinylpyridines and gives access to a variety of benzocyclobutenes (>40 examples, 32-96% yield). Notably, tri- and tetrasubstituted olefins with tertiary C(sp)-H bonds effectively delivered sterically hindered products with adjacent all-carbon quaternary centers.
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