Chemoselective, Regioselective, and <i>E</i>/<i>Z</i>-Diastereoselective Synthesis of 2-Alkylidenetetrahydrofurans by Sequential Reactions of Ambident Dianions and Monoanions
作者:Peter Langer、Esen Bellur
DOI:10.1021/jo034966f
日期:2003.12.1
A number of novel beta-ketoesters were prepared by regioselective alkylation reactions of simple beta-ketoester dianions. The cyclization of the dianions of these 1,3-dicarbonyl derivatives with 1-bromo-2-chloroethane afforded a variety of 2-alkylidenetetrahydrofurans with very good regioselectivity and E/Z-diastereoselectivity. These products were deprotonated to give novel ambident carbanions. The
Synthesis of 4-(3-hydroxyalkyl)pyrimidines by ring transformation reactions of 2-alkylidenetetrahydrofurans with amidines
作者:Esen Bellur、Peter Langer
DOI:10.1016/j.tet.2006.03.069
日期:2006.6
Domino reactions of amidines with 2-alkylidenetetrahydrofurans, prepared by cyclization of 1,3-dicarbonyl dianions or 1,3-bis-silyl enol ethers with various dielectrophiles, provided an efficient access to 4-(3-hydroxyalkyl)pyrimidines.
Synthesis of Functionalized 2-Alkylidene-tetrahydrofurans Based on a [3+2] Cyclization/Bromination/Palladium(0) Cross-Coupling Strategy
作者:Esen Bellur、Peter Langer
DOI:10.1002/ejoc.200500422
日期:2005.11
The bromination of 2-alkylidene-tetrahydrofurans and 2-alkylidene-pyrrolidines — readily available through one-pot [3+2] cyclization reactions — afforded 2-alkylidene-1′-bromotetrahydrofurans, 2-alkylidene-3-bromotetrahydrofurans and 2-alkylidene-1′,3-dibromotetrahydrofurans and their pyrrolidine counterparts. 2-Alkylidene-1′-bromotetrahydrofurans were functionalized by performing Suzuki and Heck reactions
Reaction of 2-Alkylidenetetrahydrofurans with Boron Tribromide: Chemo- and Regioselective Synthesis of 6-Bromo-3-oxoalkanoates by Application of a ‘Cyclization-Ring-Opening’ Strategy
作者:Peter Langer、Esen Bellur
DOI:10.1055/s-2004-830893
日期:——
Bromo-3-oxoalkanoates, benzofurans and 1,7-dibro- moheptan-4-ones were chemo- and regioselectively prepared by reaction of 2-alkylidenetetrahydrofurans with borontribromide.