A General and Facile Synthesis of Substituted Furans by Palladium-Catalyzed Cycloisomerization of (Z)-2-En-4-yn-1-ols
摘要:
A general and facile synthesis of furans, based on Pd(II)-catalyzed cycloisomerization of (Z)-2-en-4-yn-1-ols, is described. Cycloisomerization reactions are carried out at 25-100 degrees C in the presence of a very simple catalytic system, consisting of K2PdI4, under essentially neutral conditions. This new methodology is very versatile and can be applied to the synthesis of a variety of substituted furans, including particularly fragile, naturally occurring furans such as rosefuran. Efficient synthetic approaches for the regioselective synthesis of suitably substituted (Z)-2-en-4-yn-1-ols have been developed.
Palladium-catalyzed cycloisomerization of ( Z )-(2-en-4-ynyl)amines: a new synthesis of substituted pyrroles
作者:Bartolo Gabriele、Giuseppe Salerno、Alessia Fazio、Maria R Bossio
DOI:10.1016/s0040-4039(00)02206-1
日期:2001.2
(Z)-(2-En-4-ynyl)amines 1 bearing an internal triple bond undergo smooth cycloisomerization into pyrroles 2 in the presence of catalytic amounts of PdCl2 in conjunction with KCl at 25–100°C in anhydrous N,N-dimethylacetamide. When the triple bond is terminal, spontaneous uncatalyzed cyclization to the corresponding pyrroles takes place.
[reaction: see text] The first example of palladium-catalyzedcycloisomerization of (Z)-2-en-4-yne-1-thiols 1 to give substituted thiophenes 2 is reported. Cycloisomerization reactions are carried out under nitrogen at 25-100 degrees C in N,N-dimethylacetamide as the solvent in the presence of catalytic amounts of PdI2 in conjunction with KI to give the corresponding thiophenes in 43-94% yield.
A general and facile synthesis of furans, based on Pd(II)-catalyzed cycloisomerization of (Z)-2-en-4-yn-1-ols, is described. Cycloisomerization reactions are carried out at 25-100 degrees C in the presence of a very simple catalytic system, consisting of K2PdI4, under essentially neutral conditions. This new methodology is very versatile and can be applied to the synthesis of a variety of substituted furans, including particularly fragile, naturally occurring furans such as rosefuran. Efficient synthetic approaches for the regioselective synthesis of suitably substituted (Z)-2-en-4-yn-1-ols have been developed.
New Synthetic Approach for the Construction of Multisubstituted 2-Acyl Furans by the IBX-Mediated Cascade Oxidation/Cyclization of<i>cis</i>-2-En-4-yn-1-ols (IBX=2-Iodoxybenzoic Acid)
作者:Xiangwei Du、Haoyi Chen、Yuanhong Liu
DOI:10.1002/chem.200801561
日期:2008.10.29
An Efficient and General Synthesis of Furan-2-acetic Esters by Palladium-Catalyzed Oxidative Carbonylation of (<i>Z</i>)-2-En-4-yn-1-ols
作者:Bartolo Gabriele、Giuseppe Salerno、Francesca De Pascali、Mirco Costa、Gian Paolo Chiusoli
DOI:10.1021/jo990848+
日期:1999.10.1
A variety of (Z)-2-en-4-yn-1-ols have been carbonylated under oxidative conditions to give substituted furan-a-acetic esters in good yields. The cyclization-alkoxycarbonylation process occurs in alcoholic media at 50-70 degrees C and under 100 atm pressure of a 9:1 mixture of carbon monoxide and air in the presence of catalytic amounts of PdI2 in conjunction with KI. The proposed reaction pathway involves the in situ isomerization of the initially formed (E)-2-[(alkoxycarbonyl)methylene]-2,5-dihydrofuran species, which in some cases have been isolated and shown to be the intermediates.