- Synthesis of isocoumarins and α-pyrones via iodocyclization
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A variety of 3-substituted 4-iodoisocoumarins and 6-substituted 5-iodo-2(2H)-pyranones are readily prepared in excellent yields under mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICl.
- Yao, Tuanli,Larock, Richard C
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- Regioselective Synthesis of 5-Metalated 2-Pyrones by Intramolecular Oxymetalation of Carbonyl-ene-yne Compounds Using Indium Trihalide
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The oxyindation of carbonyl-ene-yne compounds with indium trihalides proceeded efficiently to give di-, tri-, and tetrasubstituted 2-pyrones bearing a carbon-indium bond. The metalated 2-pyrone and a zwitterion intermediate were identified by X-ray crystallographic analysis. The application of organoindium compounds to oxidation or cross-coupling provided easy access to various multifunctionalized 2-pyrones. Some 2-pyrone derivatives show intense fluorescence only in the solid state (aggregation-induced emission).
- Yata, Tetsuji,Kita, Yuji,Nishimoto, Yoshihiro,Yasuda, Makoto
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p. 14330 - 14341
(2019/11/03)
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- Synthesis of isocoumarins and α-pyrones via electrophilic cyclization
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A variety of substituted isocoumarins and α-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICl, I2, PhSeCl, p-O2NC6/
- Yao, Tuanli,Larock, Richard C.
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p. 5936 - 5942
(2007/10/03)
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- A novel route to 6-substituted and 5,6-disubstituted 2-pyrones
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6-Alkyl- and 6-(1-alkenyl)-5-iodo-2-pyrones, which are available as major products by reaction of the corresponding (Z)-2-en-4-ynoic acids with iodine and NaHCO3 in CH3CN, undergo insertion of activated zinc metal into their carbon-iodine bond to provide the corresponding 5-(iodozinc)-2-pyrones. Hydrolysis of these organometallics gives 6-substituted 2-pyrones in satisfactory yields including two natural products. On the other hand, the Pd-catalyzed reaction of the organozincs either with an activated alkenyl halide or with activated and deactivated (hetero)aryl halides provides 5,6-disubstituted 2-pyrones in fair to good yields.
- Bellina, Fabio,Biagetti, Matteo,Carpita, Adriano,Rossi, Renzo
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p. 2859 - 2863
(2007/10/03)
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- Selective synthesis of natural and unnatural 5,6-disubstituted 2(2H)-pyranones via iodolactonization of 5-substituted (Z)-2-en-4-ynoic acids
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Reaction of 5-substituted (Z)-2-en-4-ynoic acids with iodine and NaHCO3 in CH3CN or with ICl in CH2Cl2 affords mixtures of (E)-5-(1-iodoylidene)-2(5H)-furanones and 6-substituted 5-iodo-2(2H)-pyranones in which these last compounds are the major products. The 5-iodo-2(2H)-pyranones, which are easily separated chromatographically from the corresponding regioisomers, are able to undergo Stille-type reactions with a variety of organotin compounds to give 5,6-disubstituted 2(2H)-pyranones in moderate to good yields. One of these compounds, i.e. 5-(1-butynyl)-2(2H)-pyranone, has been used as direct precursor to two substances produced by fungal culture LL-11G219, which function as androgen ligands, i.e. (Z)-5-(1-butenyl)-6-methyl-2(2H)-pyranone and 5-butyl-6-methyl-2(2H)-pyranone.
- Bellina,Biagetti,Carpita,Rossi
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p. 2857 - 2870
(2007/10/03)
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