FeCl3-Catalyzed Nucleophilic Substitution of Propargylic Acetates with Enoxysilanes
摘要:
[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.
Efficient Synthetic Routes to Terminal γ-Keto−Alkynes and Unsaturated Cyclic Carbene Complexes Based on Regio- and Diastereoselective Nucleophilic Additions of Enolates on Ruthenium(II) Indenyl Allenylidenes
Ruthenium(II) indenyl allenylidene complexes [RuCCC(R1)Ph}(η5-C9H7)(PPh3)2][PF6] (R1 = Ph (1), H (2)) regioselectively react with lithium enolates LiCH2COR2 (R2 = Ph, iPr, Me, Fc, (E)-CHCHPh) at the Cγ atom to yield the neutral σ-alkynyl derivatives [RuC⋮CC(R1)Ph(CH2COR2)}(η5-C9H7)(PPh3)2] (3a−e, 4a−d). Protonation of 3a−e and 4a−d with HBF4·Et2O affords the cationic vinylidene derivatives [RuCC(H)
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
Novel Ruthenium- and Platinum-Catalyzed Sequential Reactions: Synthesis of Tri- and Tetrasubstituted Furans and Pyrroles from Propargylic Alcohols and Ketones
developed for the synthesis of substituted pyrrole derivatives from propargylic acetates, enoxysilanes and primary amines. Various aromatic and aliphatic propargylic acetates participate well in the reaction, providing the propargylation/amination/cycloisomerization products in good yields with complete regioselectivity. The one-pot multicomponent coupling reaction furnishes substituted pyrroles in high