- A concise total synthesis of biologically active frutinones via tributylphosphine-catalyzed tandem acyl transfer-cyclization
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A concise and step-economical total synthesis of biologically active frutinones has been achieved. Tributylphosphine (PBu3) efficiently induced the tandem acyl transfer-cyclization of carbonates 5 to afford 3-methoxycarbonylflavone derivatives 4 in excellent yields. Finally, concomitant deprotection and lactonization under acidic conditions furnished the desired frutinones A (1a), B (1b), and the proposed structure of frutinone C (1c).
- Yoshida, Masahito,Saito, Koya,Fujino, Yuta,Doi, Takayuki
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p. 3452 - 3458
(2014/05/06)
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- One-pot synthesis of 2-aryl-3-alkoxycarbonyl chromones through a cascade Lewis acid-catalyzed aldehyde olefination/oxa-Michael addition/oxidation
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2-Aryl-3-alkoxycarbonyl chromones were effectively constructed from aryl aldehydes and 3-(2-(methoxymethoxy) phenyl)propiolates via a cascade Lewis acid catalyzed phenol ether deprotection/aldehyde olefination/intramolecular oxa-Michael addition reaction, and a sequential oxidation. This four-step reaction could be conducted in one-pot with high atom efficiency.
- Wang, Ningning,Cai, Shuying,Zhou, Chao,Lu, Ping,Wang, Yanguang
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p. 647 - 652
(2013/07/25)
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- Alcohol mediated synthesis of 4-oxo-2-aryl-4H-chromene-3-carboxylate derivatives from 4-hydroxycoumarins
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The unusual alcohol mediated formation of 4-oxo-2-aryl-4H-chromene-3- carboxylate (flavone-3-carboxylate) derivatives from 4-hydroxycoumarins and β-nitroalkenes in an alcoholic medium is described. The transformation occurs via the in situ formation of a Michael adduct, followed by the alkoxide ion mediated rearrangement of the intermediate. The effect of the different alcohol and nonalcohol media on the reaction was investigated.
- Zanwar, Manoj R.,Raihan, Mustafa J.,Gawande, Sachin D.,Kavala, Veerababurao,Janreddy, Donala,Kuo, Chun-Wei,Ambre, Ram,Yao, Ching-Fa
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scheme or table
p. 6495 - 6504
(2012/10/08)
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- NOUVEAU MODE DE CYCLYSATION DE CETO-YLURES. APPLICATION A UNE SYNTHESE IGINALE D'ACYL-3 HYDROXY-4-COUMARINES ET DE L'HYDROXY-11 BENZO-(b) 12 XANTHONE-12
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The thermal decomposition of keto-ylides resulting from the reaction of m- and p-acetoxy benzoyl chlorides with Ph3P=CH-COOMe leads, after saponification to m- and p-phenylpropiolic acid respectively.Ortho substitution by an acyl group generally changes the orientation of the reaction.Thus o-acetoxy-, benzoyloxy- or phenylacetoxy benzoyl chlorides respectively afford: and (R=Me,Ph) in satisfactory yields.Saponification of the first and second ones gives: (R=Me, Ph).This constitutes a new, convenient route to 3-acyl 4-hydroxy cumarins and 11-hydroxy 12H-benzoxanthene 12-one.Formation of these last products involves the carbonyl of the acyloxy-substituent and not of the acyl chloride as previously observed in these series.
- Babin, P.,Dunogues, J.,Petraud, M.
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p. 1131 - 1139
(2007/10/02)
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