2128-90-7Relevant articles and documents
A novel route to 6-substituted and 5,6-disubstituted 2-pyrones
Bellina, Fabio,Biagetti, Matteo,Carpita, Adriano,Rossi, Renzo
, p. 2859 - 2863 (2001)
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.
Catalytic and selective conversion of (Z)-2-en-4-ynoic acids to either 2H-pyran-2-ones in the presence of ZnBr2 or (Z)-5-alkylidenefuran-2(5H)-ones in the presence of Ag2CO3
Anastasia, Luigi,Xu, Caiding,Negishi, Ei-Ichi
, p. 5673 - 5676 (2002)
Treatment of (Z)-5-alkyl-2-en-4-ynoic acids (1), prepared by the Pd-catalyzed alkynylzinc-β-haloacrylic acid coupling, with 5-10 mol% of ZnBr2 can produce 6-alkyl-2H-pyran-2-ones (2) along with minor amounts of (Z)-5-alkylidenefuran-2(5H)-ones (3) in >90% combined yields, with often very high (≈95/5) pyranone/furanone ratios. On the other hand, lactonization of 1 catalyzed by Ag2CO3 provides a selective synthesis of (Z)-5-alkylidenefuran-2(5H)-ones (3) in >90% yields along with minor amounts (≤5%) of 2.
Regioselective Synthesis of 5-Metalated 2-Pyrones by Intramolecular Oxymetalation of Carbonyl-ene-yne Compounds Using Indium Trihalide
Yata, Tetsuji,Kita, Yuji,Nishimoto, Yoshihiro,Yasuda, Makoto
, p. 14330 - 14341 (2019/11/03)
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).
Gold(I)-catalyzed cycloisomerization of β-alkynylpropiolactones to substituted α-pyrones
Dombray, Thomas,Blanc, Aurelien,Weibel, Jean-Marc,Pale, Patrick
supporting information; experimental part, p. 5362 - 5365 (2011/02/27)
Substituted α-pyrones were straightforwardly synthesized in good to excellent yields by a new gold(I)-catalyzed rearrangement of β-alkynylpropiolactones.
Phosphine-catalyzed synthesis of 6-substituted 2-pyrones: Manifestation of E/Z-isomerism in the zwitterionic intermediate
Zhu, Xue-Feng,Schaffner, Arnaud-Pierre,Li, Ronald C.,Kwon, Ohyun
, p. 2977 - 2980 (2007/10/03)
(Chemical Equation Presented) We report a one-step phosphine-catalyzed annulation between aldehydes and ethyl allenoate to form 6-substituted 2-pyrones. The mechanistic rationale for this reaction requires explicit discussion of the E/Z-isomerism of the zwitterionic intermediate formed by the addition of a phosphine to the allenoate. Sterically demanding trialkylphosphines facilitate the shift of equilibrium toward the E-isomeric zwitterion and lead to the formation of 6-substituted 2-pyrones. Various aromatic as well as aliphatic aldehydes undergo the transformation in moderate to excellent yield.
