A 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed selenocyclization of olefinic amides was achieved under mild reaction conditions. The reaction formed various benzeneselenyl substituted isobenzofuran-1(3H)-imine derivatives in good yields. The product was determined using single-crystal X-ray analysis. For compound 2u, the relative stereochemistry was established on the basis of NOESY NMR studies.
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http://dx.doi.org/10.1039/c8ob00179k | DOI Listing |
Chemistry
June 2024
Yunnan Key Laboratory of Metal-Organic Molecular Materials and Device, School of Chemistry and Chemical Engineering, Kunming University, 2 Puxin Road, Kunming, 650214, China.
Three hybrid electrochemical protocols, which involve the energy transfer, direct photolysis and N-hydroxyphthalimide catalyst, respectively, are presented for the selenylation/cyclization of the fragile substrates of 3-aza-1,5-dienes with diorganyl diselenides to afford 3-selenomethyl-4-pyrrolin-2-ones. The two electrophotocatalytic reactions and the indirect electrolysis one are both regioselective and external-oxidant- and transition-metal-free, and are associated with a broad substrate scope and high Se-economy, and all three methods are amenable to gram-scale syntheses, late-stage functionalizations, sunlight-induced experiments and all-solar-driven syntheses.
View Article and Find Full Text PDFOrg Lett
June 2022
School of Chemistry and Chemical Engineering, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Shanghai Jiao Tong University, Shanghai 200240, P.R. China.
An enantioselective selenocyclization of 1,1-disubstituted alkenes was achieved for the first time, which is enabled by a novel combination of a chiral BINAM-derived sulfide and an achiral Lewis acid. Various selenium-containing 4-3,1-benzoxazines, which are widely present in a range of medicinally relevant molecules, were readily obtained in moderate to good yields and good to excellent enantioselectivities. A series of tetrasubstituted carbon stereocenters were facilely constructed.
View Article and Find Full Text PDFJ Org Chem
September 2021
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India.
Arene-fused selenophenes were synthesized by a redox neutral process from arylethynyl substituted polycyclic arenes using selenium powder in refluxing -methyl-2-pyrrolidone (NMP) with the assistance of the residual water in NMP as a catalytic proton source. The site-selective nature of this selenocyclization produces -alkenes as a competitive product, which is dependent on the π-electron donation ability of polycyclic arenes and the kind of arylethynyl group attached to it. DFT calculations were performed to understand the site selectivity in the selenophene formation reaction.
View Article and Find Full Text PDFOrg Biomol Chem
March 2018
State Key Laboratory of Virology, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China. and Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
A 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed selenocyclization of olefinic amides was achieved under mild reaction conditions.
View Article and Find Full Text PDFJ Org Chem
December 2017
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
A synthesis of allahabadolactone A is described employing diastereoselective Diels-Alder and selenocyclization reactions, starting from (R)-citronellal and propylene oxide. The Diels-Alder substrate is built up in an efficient manner by rhodium-catalyzed alkyne hydroboration and palladium-catalyzed coupling reactions of E-1,2-dichloroethene. It is observed that the Diels-Alder reaction only displays high diastereoselectivity when the diene bears an additional alkene substituent but not an alkyne substituent.
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