We report the one-pot synthesis of 4-amino thiochromans using simple aminocyclopropanes and thiophenols through a formal [3+3] annulation reaction. This reaction proceeds under mild conditions with good functional group tolerance. The thiochroman core was formed with complete regioselectivity, and modification of complex drug molecules containing an aminocyclopropane was also realized.
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http://dx.doi.org/10.1021/acs.orglett.0c03528 | DOI Listing |
Org Lett
January 2025
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Highly asymmetric (3+3) annulation of diaziridines with oxiranes via C-N bond cleavage in diaziridine was achieved under 10 mol % of chiral copper(II) complex as the catalyst under mild reaction conditions. With Cu(OTf) as the Lewis acid and C-symmetric imidazolidine-pyrroloimidazolone pyridine as the ligand, diverse tetrahydro-[1,3,4]-oxadiazines were obtained by stereospecific C-N/C-O bond formation in moderate to good yields (up to 93% yield) and high diastereo- (>20:1 dr) and enantioselectivities (up to 92% ee). The catalytic cycle and stereochemical model were proposed by DFT calculation.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram 695019, India.
We have devised a copper-catalysed tandem annulation reaction to generate a new class of bicyclic nucleoside analogues (BCNAs), namely, amino-substituted thiazolopyrimidine ribonucleosides. The reaction between triacetyl-5-iodo-cytidine and an appropriate organic isothiocyanate in the presence of a Cu salt and ligand resulted in the formation of an amino-substituted thiazolopyrimidine moiety. This reaction was found to be compatible with a range of aliphatic and aromatic isothiocyanates, affording the corresponding products in moderate to good yields.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Mulliken Center for Theoretical Chemistry University of Bonn Beringstr. 4, 53115 Bonn, Germany.
A novel HSO-catalyzed ANRORC-type rearrangement of pyrazinones to imidazoles proceeding through pyridazino[]annulation with simultaneous introduction of a pyrazole ring at position 2 of the imidazole system has been developed, which offers efficient and expedited access to new biheterocyclic systems - 2-(pyrazol-3-ul)imidazoles and 2-(pyrazol-3-yl)imidazo[4,5-]pyridazines. Diverse bi--heterocyclic systems with the imidazo[4,5-]pyridazine-4,7-diamine moiety could be obtained in excellent yield when 5,6-dicyano-3-(2-oxo-2-ethyl)pyrazin-2(1)-ones interact with hydrazines the selective spiro-formation in a tandem ring-opening/ring-closing process, which allowed the simultaneous construction of five new C-N bonds. This new method is compatible with an array of functional groups, proceeds under mild reaction conditions with the involvement of commercially available reagents.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Science, China Pharmaceutical University, Nanjing 210009, P. R. China.
J Org Chem
January 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, South China University of Technology, Guangzhou 510640, China.
The chemoselective defluorinative [3 + 3] annulation of (trifluoromethyl)alkenes with thioureas is reported. This protocol affords various attractive 6-fluoro-3,4-dihydropyrimidine-2(1)-thiones in high yields, features transition-metal free, mild conditions, efficient, is operationally simple and gram-scalable, tolerates diverse useful functional groups.
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