Furans versus 4H-pyrans: catalyst-controlled regiodivergent tandem Michael addition–cyclization reaction of 2-(1-alkynyl)-2-alken-1-ones with 1,3-dicarbonyl compounds
Furans versus 4H-pyrans: catalyst-controlled regiodivergent tandem Michael addition–cyclization reaction of 2-(1-alkynyl)-2-alken-1-ones with 1,3-dicarbonyl compounds
作者:Yuanjing Xiao、Junliang Zhang
DOI:10.1039/b905267d
日期:——
The DBU-catalyzed reaction of 1-(1-alkynyl)-2-alken-1-ones with 1,3-dicarbonyl compounds produces 4H-pyrans in moderate to excellent yield, whereas the cationic Pd(II)-catalyzed reaction affords furans regioselectively.
Phase-transfer-catalyzed cyclization reaction of nucleophilic addition to electron-deficient 1,3-conjugated enynes for the synthesis of functionalized 4H-pyrans
作者:Jie Hu、Lei Liu、Shangdong Yang、Yong-Min Liang
DOI:10.1039/c0ob01255f
日期:——
A variety of substituted 4H-pyrans are readily prepared in moderate to good yields under the mild reaction conditions by nucleophilic addition to electron-deficient 1,3-conjugated enynes with phase-transfer catalysis (PTC).