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.
A facile synthesis of tetrasubstituted 2,3-dihydrofuran derivatives using poly(ethylene glycol) as soluble support
作者:Chun Feng、Cuifen Lu、Zuxing Chen、Nianguo Dong、Jiawei Shi、Guichun Yang
DOI:10.1002/jhet.372
日期:——
A facile synthesis of tetrasubstitude 2,3-dihydrofurans has been conducted using poly(ethylene glycol) (PEG) as a soluble polymer support. The PEG-supported pyridinium ylides react with 3-arylidene-2,4-pentanedione in the presence of triethylamine (TEA) via conjugate addition to form PEG-supported dihydrofuran derivatives, being cleaved by 1% KCN/EtOH to afford trans-tetrasubstitude-2,3-dihydrofurans
Highly Diastereoselective and Enantioselective Formal [4 + 1] Ylide Annulation for the Synthesis of Optically Active Dihydrofurans
作者:Jun-Cheng Zheng、Chun-Yin Zhu、Xiu-Li Sun、Yong Tang、Li-Xin Dai
DOI:10.1021/jo801135j
日期:2008.9.1
On the basis of the reactions of camphor-derived sulfur ylide with alpha-ylidene-beta-diketones, highly efficient and selective synthesis of opticallyactive dihydrofurans has been achieved.
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).