An unprecedented [2+2+1] hydrative annulation of 1,6-enynes with terminal alkynes is achieved using catalytic cationic Rh(I). Thus, a modular assembly of cyclopenta[b]benzofuranols with two consecutive quarternary stereocenters is achieved from readily available alkynes. The reaction is proposed to go through a sequence of 5-membered rhoda-cycle formation, regioselective acetylene insertion, 1,5 H-shift, substrate controlled stereoselective addition of water molecule followed by 1,2-rhodium migration gave contracted rhoda-cycle D and reductive elimination. Necessary control/labelling experiments were conducted to gain insight in to the mechanism.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/chem.202102930 | DOI Listing |
Org Lett
July 2024
Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan.
A unique type of platinum catalysis that is valuable for the synthesis of α,β-unsaturated ketones is described. In the presence of PtCl, (2-arylethynyl)trimethylsilanes reacted with HO at 30 °C to give 1,4-diarylbut-3-en-2-ones in moderate to good yields. (2-Alkylethynyl)trimethylsilanes could be efficiently converted into the corresponding hydrative dimerization products by a modified Pt catalyst system.
View Article and Find Full Text PDFSmall
June 2024
Department of Physics and Chemistry, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungang-daero, Dalseong-gun, Daegu, 42988, Republic of Korea.
Metal-organic cages (MOCs) have garnered significant attention due to their unique discrete structures, intrinsic porosity, designability, and tailorability. However, weak inter-cage interactions, such as van der Waals forces and hydrogen bonding can cause solid-state MOCs to lose structural integrity during desolvation, leading to the loss of porosity. In this work, a novel strategy to retain the permanent porosity of Cu-paddlewheel-based MOCs, enabling their use as heterogeneous catalysts is presented.
View Article and Find Full Text PDFOrg Lett
November 2023
Chang-Kung Chuang Institute, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Lu, Shanghai 200241, China and.
The Cloke-Wilson rearrangement of unsymmetrical β-diketone-derived cyclopropanes inevitably yields a mixture of two 4-acylated 2,3-dihydrofuran regiomers. By using alkynes as masked acyls, TfNH-promoted Cloke-Wilson rearrangement of polysubstituted 1-(1-alkynyl)cyclopropyl ketones followed by alkyne hydration is described, regioselectively affording 2,3-dihydrofurans bearing 4-acyls nonequivalent to that involved in the Cloke-Wilson rearrangement. The 2,3-dihydrofuran rings with 2,3-diaryls are unexpectedly more stable than their diastereomers under the reaction conditions, guaranteeing the regiospecificity of this hydrative Cloke-Wilson rearrangement with high fidelity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2023
Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38, 1090, Vienna, Austria.
α-Amino acid derivatives are key components of the molecules of life. The synthesis of α-amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis. Herein, we report a practical method for the preparation of α-amino acid derivatives via direct hydrative amination of activated alkynes under mild conditions, relying on sulfinamides as the nitrogen source.
View Article and Find Full Text PDFChemistry
December 2021
Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India.
An unprecedented [2+2+1] hydrative annulation of 1,6-enynes with terminal alkynes is achieved using catalytic cationic Rh(I). Thus, a modular assembly of cyclopenta[b]benzofuranols with two consecutive quarternary stereocenters is achieved from readily available alkynes. The reaction is proposed to go through a sequence of 5-membered rhoda-cycle formation, regioselective acetylene insertion, 1,5 H-shift, substrate controlled stereoselective addition of water molecule followed by 1,2-rhodium migration gave contracted rhoda-cycle D and reductive elimination.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!