Base-induced intramolecularcyclization of novel (4-aryl-2,4-dioxobutyl)methylphenylsulfonium salts prepared from the commercially available 1-arylethanone by a cost-effective process is described in this paper. The reaction was completed within 10 min to produce a family of 2-unsubstituted 5-aryl-3(2H)-furanones in excellent yield. This procedure is simple, and can be carried out under mild conditions
作者:J.Edward Semple、Anne E. Guthrie、Madeleine M. Joullié
DOI:10.1016/s0040-4039(00)74551-5
日期:1980.1
A novel cyclization reaction is described which affords readily manipulable 3(2H)-dihydrofuranone ethylene ketals, useful in the total synthesis of an ascofuranone model, bullatenone, and muscarine analogs.
Anionic activation by fluoride ion in solid-liquid systems
作者:S. Sebti、A. Foucaud
DOI:10.1016/s0040-4020(01)87355-5
日期:1986.1
and 2-acyloxy 3-oxo 2,3-diphenylpropanamides 13 under anionic activation by cesium fluoride was studied. The fluoride ion is an efficient base for the heterocyclization of 1 into 3 (2H)-furanones and 2 (5H)-furanones, but the hydrolysis of the ester group lowered the selectivity of the reaction. However, the cleavage of 13 into the esters 14 and the cyclization of 3-benzoyloxy 3-methyl 2-butanone into
The combination of (p-CF3C6H4)3PAuCl and AgOTf generates a powerful catalyst for the intramolecular cyclizations of readily available γ-hydroxyalkynones under mild conditions. The substituted 3(2H)-furanones are obtained in 55−94% yields. This method is also applicable to the preparation of 2,3-dihydro-4H-pyran-4-ones.
(p -CF 3 C 6 H 4)3 PAuCl和AgOTf的组合为在温和条件下易于获得的γ-羟基炔酮的分子内环化生成了强大的催化剂。取代的3(2 H)-呋喃酮的产率为55-94%。该方法也适用于制备2,3-二氢-4 H-吡喃-4-酮。
Pd(II)-Catalyzed Cascade Wacker−Heck Reaction: Chemoselective Coupling of Two Electron-Deficient Reactants
acrylate, two electron-deficient reactants. With β-hydroxy ynones, this cascade Wacker−Heck process gave access to highly functionalized tri- or tetrasubstituted dihydropyranones featuring an unusual dienic system. For diastereomerically pure and for enantioenriched β-hydroxyynones, these reactions proceed without affecting the stereochemical integrity of the existing stereocenters. In addition, tetrasubstituted