approach for the synthesis of α-pyrones via Baeyer–Villiger-type oxidation of α-iodocyclopentenones through a catalyst- and additive-free system using air as an environmentally benign oxidant is described. The reaction exhibits excellent functional group compatibility and provides a simple and efficient protocol for the construction of highly functionalized α-pyrones under mild reaction conditions.
Rh(III)-Catalyzed [3 + 3] Annulation Reaction of Cyclopropenones and Sulfoxonium Ylides toward Trisubstituted 2-Pyrones
作者:Peng Zhou、Wei-Tao Yang、Anis Ur Rahman、Guigen Li、Bo Jiang
DOI:10.1021/acs.joc.9b02253
日期:2020.1.17
A new Rh(III)-catalyzed [3 + 3] annulation reaction between cyclopropenones and β-ketosulfoxonium ylides has been reported, enabling metal carbene insertion to access a wide range of trisubstituted 2-pyrones with moderate to excellent yields via C-C single-bond cleavage, in which sulfoxonium ylides serve as potential safe precursors of metal carbenes. This reaction occurred under redox-neutral conditions
Organic synthesis using carbon monoxide. Regiospecific cobalt mediated synthesis of 2H-pyran-2-ones
作者:William P. Henry、Russell P. Hughes
DOI:10.1021/ja00284a077
日期:1986.11
Synthese des composes du titre a partir de Co(CO) 4 − et de cyclopropenylium via les η 3 -oxocyclobutenyl complexes de cobalt carbonyle
Synthese des composes du titre a partir de Co(CO) 4 − et de cyclopropenylium via les η 3 -oxocyclobutenyl complexes de Coco(CO) 4 − et de cyclopropenylium
Transition‐metal free synthesis of
<scp>2‐pyrones</scp>
by [3 + 3] annulation of cyclopropenones and sulfur ylides
A simple and efficient synthesis for 2-pyrones by [3 + 3] annulation of cyclopropenones and sulfur ylides in the presence of triethyl amine as a base has been developed featuring transition-metal free conditions, high yields, and excellent functional group compatibility. Using this process, a variety of 2-pyrones were prepared in good to excellent yields.
An efficient palladium-catalyzed cross-coupling reaction of 4-hydroxy-pyrone or 4-hydroxy-2(5H)-furanone with arylboronic acid is described, which affords the 4-substituted-pyrones and 2(5H)-furanones in good yields. This transformation proceeds through a C-OH bond activation under mild conditions. (C) 2011 Elsevier Ltd. All rights reserved.