A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.
Novel Domino Reactions of (<i>Z</i>,<i>Z</i>)-2,2′-Thiobis(1,3-diarylprop-2-en-1-ones) with Acetylacetone and Ethyl Acetoacetate: Stereoselective Synthesis of Highly Functionalized Dihydrofurans
Abstract The domino reactions of (Z,Z)-2,2′-thiobis(1,3-diarylprop-2-en-1-ones) with acetylacetone and ethylacetoacetate in the presence of sodium ethoxide afforded the corresponding 4,5-dihydrofurans stereoselectively in moderate yields presumably via a Michael addition–enolization–displacement sequence.
A Novel Facile Synthetic Route to Highly Substituted 2,3-Dihydrofurans via Ammonium Ylides
作者:Yongmin Liang、Zhanjun Yang、Mingjin Fan、Weimin Liu
DOI:10.1055/s-2005-869956
日期:——
Tetrasubstituted 2,3-dihydrofurans derivatives were prepared via the reaction of quaternary ammonium salts 1 with electrophilic alkenes 2 in the presence of powered K2CO3, usually in a stereoselective manner with good to high yields. The stereochemistry of dihydrofurans was secured by NMR signals and subsequently confirmed by X-ray diffraction.
Simple Approach to the High Stereoselective Synthesis of<i>trans</i>‐2,3‐Dihydrofuran Derivatives
作者:Weiguo Cao、Guodong Chen、Jie Chen、Rongqing Chen
DOI:10.1081/scc-200049776
日期:2005.3
presence of K2CO3, benzoylmethyltriphenylarsonium bromide 1 reacted with 3‐arylidene‐2,4‐pentadione 2 in benzene under heating to give 2‐benzoyl‐3‐aryl‐4‐acetyl‐5‐methyl‐trans‐2,3‐dihydrofurans 3 in good yield with high stereoselectivity.
Treatment of halides 5 with electrophilic alkenes 2 afforded the corresponding dihydrofurans 3 and 4 in the presence of 1, 4-diazabicyclo[2.2.2]octane (DABCO) with good to excellent yields and in a stereoselective manner in most cases. Moreover, the stereoisomers 3 and 4 could be easily transformed each other in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).