A tandem dienone photorearrangement-cycloaddition (DPC) reaction of novel cyclohexadienone substrates tethered with various 2π and 4π reaction partners resulted in the formation of polycyclic, bridged frameworks. In particular, use of alkynyl ether-tethered substrates led to (3 + 2) cycloaddition to afford strained alkenes which could be further elaborated by intra- and intermolecular cycloaddition chemistry to produce complex, polycyclic chemotypes.
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http://dx.doi.org/10.1021/ja409992m | DOI Listing |
Org Lett
August 2021
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India.
Photoirradiation of (6,9)-zerumbone-2,3-epoxide afforded a diverse range of transannular cyclized products in the presence of a catalytic amount of Sc(OTf). At the behest of the geometrical isomers produced by photoirradiation, the diversity encompasses an unprecedented eudesmane core and oxo-bridged hydroxy-olefin skeletons. Structure elucidation and the stereochemical outcome of the products are described via extensive NMR analysis.
View Article and Find Full Text PDFJ Org Chem
August 2019
Department of Organic Synthesis and Process Chemistry , CSIR-Indian Institute of Chemical Technology, Hyderabad 500007 , India.
A metal free DBU catalyzed synthesis of 1,2,3-triazole-fused dihydrobenzoxazinone derivatives by tandem β-azidation/[3 + 2] cycloaddition reaction has been developed under mild conditions. The methodological studies offer a broad scope and proceed well with a wide range of alkynylated cyclohexa 2,5-dienones, giving new -triazole-fused tricyclic scaffolds.
View Article and Find Full Text PDFFront Chem
September 2018
Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
The proteasome is a validated target in drug discovery for diseases associated with unusual proteasomal activity. Here we report that two diphenyldihaloketones, CLEFMA and EF24, inhibit the peptidase activity of the 26S proteasome. The objective of this study was to investigate interaction of these compounds with the proteasome and identify a putative target within the protein components of the 26S proteasome.
View Article and Find Full Text PDFOrg Lett
April 2017
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Nanlu, Lanzhou 730000, China.
A novel base-mediated tandem spirocyclopropanation/rearrangement reaction of vinyl p-quinone methides (p-VQMs) with sulfonium salts is described. The unprecedented reactivity of p-VQMs was explored for the first time in the spiroannulation cascade, providing a stereoselective approach to the construction of synthetically interesting, densely functionalized spirocyclopentenyl p-dienones.
View Article and Find Full Text PDFJ Org Chem
March 2017
Hunter Laboratory, Department of Chemistry, Clemson University, Clemson, South Carolina 29634-0973, United States.
Alkyl Grignard reagents (Et, Bu, Pr, cyclohexyl), with the exception of BuMgCl, undergo exclusive or exceptionally highly regioselective 1,4-addition reactions to α,β-γ,δ-unsaturated ketones, while aryl and heteroaryl Grignard reagents give mixed results ranging from exclusive 1,4-addition (1-naphthyl, 2-N-methylpyrrolyl) to regioselective 1,2-addition (2-furyl, 2:1). All alkyl, aryl, and heteroaryl Grignard reagents examined gave exclusive 1,4-addition reactions with α,β-γ,δ-unsaturated thiol esters, with the exception of BuMgCl, which gave an 80:20 mixture of 1,4:1,6-addition products. The high chemo- and regioselectivity observed for these reactions is attributed to a radical or radical-like pathway for the alkyl Grignard reagents and possibly a carbanion pathway for aryl Grignard reagents.
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