- Efficient catalyst for tandem solvent free enantioselective Knoevenagel-formal [3+3] cycloaddition and Knoevenagel-hetero-Diels-Alder reactions
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In this study a highly efficient catalyst has been observed for tandem solvent free enantioselective Knoevenagel-formal [3+3] cycloaddition and Knoevenagel-hetero-Diels-Alder reactions. Thus, the synthesis of bicyclic tetrahydro-2H-chromen-5(6H)-one and tricyclic octahydro-2H-benzo[c]-chromen-1(6H)-one derivatives with enantioselectivity up to ee 99% has been achieved in the presence of a chiral Lewis acid assisted Bronsted acid (LBA), titanium-isopropoxy-(S)-BINOLate under solvent free conditions. The stereochemistry of the tricyclic product 10 has been further supported by single crystal X-ray analysis. This domino powerful strategy combines both the economic and environmental aspects of organic chemistry, which are necessary for academic and industrial applications.
- Fernandes, Sylvia,Rajakannu,Bhat, Sujata V.
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- Thermal isomerization of cannabinoid analogues
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(Chemical Equation Presented) Thermal isomerization of CBCan to THCan [nonaromatic analogues of plant cannabinoids cannabichromene (CBC) and Δ1-tetrahydrocannabinol (THC), respectively] is predicted in silico and demonstrated experimentally. Density functional theory calculations support a similar isomerization mechanism for the corresponding plant cannabinoids. Docking studies suggest that THCan, although nonaromatic, has a CB1 receptor binding affinity similar to that of natural THC.
- Garcia, Angie,Borchardt, Dan,Chang, Chia-En A.,Marsella, Michael J.
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Read Online
- USE OF COMPOSITIONS OBTAINED BY CALCINING PARTICULAR METAL-ACCUMULATING PLANTS FOR IMPLEMENTING CATALYTICAL REACTIONS
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The use of metal-accumulating plants for implementing chemical reactions especially catalytical reactions.
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Paragraph 0844; 0845
(2016/01/25)
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- Enantioselective wacker-type cyclization of 2-alkenyl-1,3-diketones promoted by Pd-SPRIX catalyst
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(Equation Presented). An enantioselective intramolecular Wacker-type cyclization of 2-alkenyl-1,3-diketones catalyzed by a Pd(II)-SPRIX complex was developed. The reaction proceeded in a 6-endo-trig mode to give the desired chromene derivatives with moderate to good enantioselectivity. Isomerization of C-C double bonds via a π-allyl Pd intermediate was involved as the key step.
- Takenaka, Kazuhiro,Mohanta, Suman C.,Patil, Mahesh L.,Rao, C. V. Laxman,Takizawa, Shinobu,Suzuki, Takeyuki,Sasai, Hiroaki
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supporting information; experimental part
p. 3480 - 3483
(2010/09/16)
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- Environmentally benign, one-pot synthesis of pyrans by domino Knoevenagel/6π-electrocyclization in water and application to natural products
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In water medium, environmentally benign, facile, and efficient synthesis of pyrans was achieved in good yields by the reactions of a variety of cyclic 1,3-dicarbonyls with several α,β-unsaturated aldehydes. The key strategy was a formal [3+3] cycloaddition by domino Knoevenagel/6π- electrocyclization. This methodology was applied to the synthesis of biologically interesting pyranocoumarin, pyranoquinolinone, and pyranonaphthoquinone derivatives along with selected natural and non-natural products. The Royal Society of Chemistry 2010.
- Jung, Ene Jin,Park, Byung Ho,Lee, Yong Rok
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experimental part
p. 2003 - 2011
(2011/02/19)
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- Metal-free Bronsted acid catalyzed formal [3 + 3] annulation. Straightforward synthesis of dihydro-2H-chromenones, pyranones, and tetrahydroquinolinones
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(Chemical Equation Presented) Bronsted acids catalyze the addition of enolizable β-diketones, β-ketoesters, and vinylogous amides to α,β-unsaturated aldehydes to lead to substituted chromenones, pyranones, and tetrahydroquinolinones in good yields under mild reaction conditions via a formal [3 + 3] cycloaddition.
- Moreau, Julie,Hubert, Claudie,Batany, Jessika,Toupet, Loic,Roisnel, Thierry,Hurvois, Jean-Pierre,Renaudz, Jean-Luc
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supporting information; experimental part
p. 8963 - 8973
(2010/03/04)
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- Synthesis of spinochalcone B and analogues
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An efficient synthesis of spinochalcone B and its analogues is achieved from readily available 2H-pyran. Copyright Taylor & Francis Group, LLC.
- Lee, Yong,Wang, Xue,Kim, Byung
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p. 2017 - 2025
(2007/10/03)
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- A concise route for the synthesis of biologically interesting pyranocoumarins - Seselin, (±)-cis-khellactone, (±)- quianhucoumarin D, and the (±)-5-deoxyprotobruceol-I regioisomer
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An efficient synthesis of pyranocoumarins is achieved starting from 2H-pyrans. This process provides naturally occurring seselin, cis-khellactone, quianhucoumarin D, and the 5-deoxyprotobruceol-I regioisomer. Georg Thieme Verlag Stuttgart.
- Lee, Yong Rok,Lee, Won Kyong,Noh, Seok Kyun,Lyoo, Won Seok
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p. 853 - 859
(2007/10/03)
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- A Lewis acid-catalyzed formal [3 + 3] cycloaddition of α,β- unsaturated aldehydes with 4-hydroxy-2-pyrone, diketones, and vinylogous esters
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A Lewis acid-catalyzed formal cycloaddition of α,β-unsaturated aldehydes with 6-methyl-4-hydroxy-2-pyrone, 1,3-diketones, and vinylogous silyl esters is described here.
- Kurdyumov, Aleksey V.,Lin, Nan,Hsung, Richard P.,Gullickson, Glen C.,Cole, Kevin P.,Sydorenko, Nadiya,Swidorski, Jacob J.
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p. 191 - 193
(2007/10/03)
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