J Org Chem
Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran 15418-49611, Iran.
Published: November 2024
A practical approach for rapid and efficient access to spirocyclic isobenzofurans is described. The reaction proceeds through the cycloaddition of 1,6-ynenone derivatives and 4-nitro-1,3-diarylbutan-1-ones, promoted by CsCO in the presence of -proline as a catalyst. The advantages of this reaction include the formation of two C-C bonds and one C-O bond as well as mild reaction conditions. Extended spirocyclic isobenzofurans are obtained with good efficiency and diastereoselectivity under these mild conditions, and this new protocol avoids the use of any transition-metal reagents.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.joc.4c01890 | DOI Listing |
J Org Chem
November 2024
Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran 15418-49611, Iran.
A practical approach for rapid and efficient access to spirocyclic isobenzofurans is described. The reaction proceeds through the cycloaddition of 1,6-ynenone derivatives and 4-nitro-1,3-diarylbutan-1-ones, promoted by CsCO in the presence of -proline as a catalyst. The advantages of this reaction include the formation of two C-C bonds and one C-O bond as well as mild reaction conditions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2022
Department of Chemistry and Biochemistry, Baylor University, One Bear Place, 97348, Waco, Texas 76798, USA.
Described herein are the first total syntheses of (±)-dracocephalone A (1) and (±)-dracocequinones A (4) and B (5). The synthesis was initially envisioned as proceeding through an intramolecular isobenzofuran Diels-Alder reaction, a strategy that eventually evolved into a Lewis acid-promoted spirocyclization. This highly diastereoselective transformation set the stage for trans-decalin formation and a late-stage Suárez oxidation that produced a [3.
View Article and Find Full Text PDFJ Org Chem
November 2016
Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China.
An efficient ring-contraction reaction of isochromeno[4,3-b]indol-5(11H)-ones via a nucleophile-induced disproportionation/spirocyclization cascade process has been developed under mild conditions. The process realized the conversion of isochromeno[4,3-b]indol-5(11H)-ones into N-unsubstituted spiro[indoline-2,1'-isobenzofuran]-3,3'-diones and spiro[indoline-2,1'-isoindoline]-3,3'-diones in the absence of a transition-metal catalyst or oxidant. Gram-scale reaction further demonstrated the practicability of the protocol.
View Article and Find Full Text PDFJ Org Chem
July 2007
Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala Biomedical Centre, Uppsala University, Box 574, SE-751 23 Uppsala, Sweden.
A number of new spiro[cyclohexane-1,1'-isobenzofuran]-based compounds was synthesized by palladium(0)-catalyzed 5-exo cyclization of a series of cyclohexenyl o-halobenzyl ethers. Controlled microwave heating was found to promote both product yield and reaction rate without compromising the selectivity. Heck cyclization of aryl iodide 6, 2-(2-iodobenzyloxy)cyclohex-2-enyl acetate, proceeded selectively without involvement of the allylic acetate functionality.
View Article and Find Full Text PDFJ Org Chem
April 2001
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Ammonium ylides derived from the Cu(II)-catalyzed decomposition of alpha-diazo carbonyls tethered to tertiary amines underwent a benzylic Stevens [1,2]-rearrangement to give tetrahydroisoquinolines or benzazepines containing fused five-membered rings, a feature found in the cephalotaxus alkaloids. Model studies were also carried out toward the synthesis of lennoxamine, a member of the isoindolobenzazepine family of alkaloids. The approach utilized is based on the Rh(II)-catalyzed reaction of an alpha-diazo carbonyl compound containing an amido group in the gamma-position.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!
© LitMetric 2025. All rights reserved.