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).
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.