Copper(II) Triflate-Catalyzed Nucleophilic Substitution of Propargylic Acetates with Enoxysilanes. A Straightforward Synthetic Route to Polysubstituted Furans
作者:Zhuang-ping Zhan、Shao-pei Wang、Xu-bin Cai、Hui-juan Liu、Jing-liang Yu、Yuan-yuan Cui
DOI:10.1002/adsc.200700234
日期:2007.9.3
A novel and efficient procedure for the synthesis of γ-alkynyl ketones by the nucleophilic substitution of propargylic acetates with enoxysilanes in the presence of a catalytic amount of Copper(II) triflate, has been developed. The substitution reaction can be followed by a 4-toluenesulfonic acid-catalyzed cyclization without purification of the γ-alkynyl ketone intermediates, offering a straightforward
Ir-Catalyzed Substitution of Propargylic-type Esters with Enoxysilanes
作者:Isamu Matsuda、Ken-ichi Komori、Kenji Itoh
DOI:10.1021/ja0264089
日期:2002.8.1
Propargylic-type acetates react readily with enoxysilanes in the presence of 1 mol % of [Ir(cod)P(OPh)3}2]OTf activated preliminarily with molecular H2 to give beta-alkynyl ketones in high to excellent yields. Substitution at the propargyl carbon proceeds exclusively or selectively in most types of propargylic esters. Alternatively, the formation of the allenyl products is predominant in the reaction of esters, which have two phenyl groups on the propargyl carbon.
FeCl<sub>3</sub>-Catalyzed Nucleophilic Substitution of Propargylic Acetates with Enoxysilanes
作者:Zhuang-ping Zhan、Xu-bin Cai、Shao-pei Wang、Jing-liang Yu、Hui-juan Liu、Yuan-yuan Cui
DOI:10.1021/jo701782g
日期:2007.12.1
[Graphics]An efficient FeCl3-catalyzed substitution reaction of propargylic acetates with enoxysilanes under mild conditions to afford corresponding gamma-alkynyl ketones has been developed. The substitution reaction is followed by a TsOH-catalyzed cyclization without purification of the gamma-alkynyl ketone intermediates, offering a straightforward synthetic route to tri- or tetrasubstituted furans.
Gold-catalyzed cycloisomerization of alk-4-yn-1-ones
作者:Volker Belting、Norbert Krause
DOI:10.1039/b819704k
日期:——
Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones 1 affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans 2, whereas a 6-endo-digcyclization to 4H-pyrans 3 is observed with substrates bearing two substituents at C-3. In alcoholic solvents