α-Diimine niobium complexes serve as catalysts for deoxygenation of benzyl ethers by silicon tetrachloride (SiCl) to cleanly give two equivalents of the corresponding benzyl chlorides, where SiCl has the dual function of oxygen scavenger and chloride source with the formation of a silyl ether or silica as the only byproduct. The reaction mechanism has two successive trans-etherification steps that are mediated by the niobium catalyst, first forming one equivalent of benzyl chloride along with the corresponding silyl ether intermediate that undergoes the same reaction pathway to give the second equivalent of benzyl chloride and silyl ether.
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http://dx.doi.org/10.1021/acs.inorgchem.9b01784 | DOI Listing |
Acc Chem Res
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes.
View Article and Find Full Text PDFJ Org Chem
January 2025
Laboratory of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan.
A one-pot, telescoped transformation of silyl ethers into cyanides that proceeds via silyl-ether oxidation mediated by nitroxyl-radical catalyst and [bis(trifluoroacetoxy)iodo]benzene followed by an imine formation-oxidation sequence using iodine and aqueous ammonia is reported. This transformation is effective for the site-selective transformation of benzylic and allylic silyl ethers in the presence of other silyl ethers. Using an -protected oxime and a catalytic amount of triflic acid instead of iodine/aqueous ammonia is also effective for cyanation.
View Article and Find Full Text PDFCarbohydr Res
January 2025
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India. Electronic address:
The synthesis of 2-hydroxy analogues of castanospermine from two new iminooctitols via Mitsunobu cyclization is described. The iminooctitols were derived from the dihydroxylation of an allyl alcohol intermediate, obtained by adding vinylmagnesium bromide to the C6-aldehyde of a protected 1-deoxynojirimycin. An orthogonally protected hemiacetal with silyl group at the C6-hydroxy position and remaining as benzyl ethers, synthesized in four steps from d-glucose, served as a building block in the synthesis of the 1-deoxynojirimycin intermediate.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, Shandong University, Jinan 250100, P. R. China.
Herein, we describe a hexavalent tellurium-based chalcogen bonding catalysis platform capable of addressing reactivity and selectivity issues. This research demonstrates that hexavalent tellurium salts can serve as a class of highly active chalcogen bonding catalysts for the first time. The tellurium centers in these hexavalent catalysts have only one exposed interaction site, thus providing a favorable condition for the controlling of reaction selectivity.
View Article and Find Full Text PDFTetrahedron
February 2025
Department of Chemistry, Western Washington University, Bellingham, WA 98225 (USA).
Beta-hydroxy ketones can be reduced using a sequence of ruthenium-catalyzed silyl etherification followed by tetrabutylammonium fluoride (TBAF) promoted intramolecular hydrosilylation. Switching from TBAF to tetrabutylammonium difluorotriphenylsilicate (TBAT), even without first forming the silyl ether, gave cyclic dioxasilinane products. These somewhat sensitive compounds could be isolated pure by column chromatography using florisil as the stationary phase.
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