Gold-Catalyzed Approach to Multisubstituted Fulvenes via Cycloisomerization of Furan/Ynes
摘要:
A new approach to functionalized fulvenes with an enone or enal moiety has been developed through gold-catalyzed intramolecular cycloisomerization of furan/ynes with a two-carbon tether in between the furan and the triple bond. The reaction proceeds with complete regioselectivity via a 6-endo-cyclization and high stereoselectivity. Moreover, the E- or Z-stereochemistry of the double bond in fulvene products can be easily controlled by performing the reaction in different solvents.
Synthesis of 2-Tetrazolyl-Substituted 3-Acylpyrroles via a Sequential Ugi-Azide/Ag-Catalyzed Oxidative Cycloisomerization Reaction
作者:Han-Han Kong、Hong-Ling Pan、Ming-Wu Ding
DOI:10.1021/acs.joc.8b01984
日期:2018.10.19
cascade cycloisomerization/aerobic oxidation reaction of a Ugi-azide adduct for the preparation of 3-acylpyrroles using molecular oxygen as the terminal oxidant has been developed. A series of 2-tetrazolyl-substituted 3-acylpyrroles were obtained in 62–89% yields from readily available enynals 1, primaryamines2, isocyanides 3, and trimethylsilyl azide 4 in the presence of a catalytic amount of AgNO3 and
NHC-Catalyzed Chemoselective Reactions of Enals and Cyclopropylcarbaldehydes for Access to Chiral Dihydropyranone Derivatives
作者:Yingling Nong、Chen Pang、Kunpeng Teng、Sheng Zhang、Qian Liu
DOI:10.1021/acs.joc.3c01171
日期:2023.10.6
An N-heterocyclic carbene (NHC)-catalyzed chemoselective activation reaction of 1-cyclopropylcarbaldehydes and α-alkynyl enals is reported. NHC selectively catalyzes 1-cyclopropylaldehydes, followed by a [2 + 4] cycloaddition reaction with α-alkynyl enals. The target dihydropyranone derivatives bearing different substituents and substitution patterns can be obtained in good to excellent yields with
Efficient AgOTf or Ph3PAuCl–AgSbF6 catalyzed cyclization of 1-hydroxy-2-alkynylallylphosphonates/2-alkynylallyl alcohols to 2-furylphosphonates/2,3,5-trisubstituted furans
作者:Ramesh Kotikalapudi、K.C. Kumara Swamy
DOI:10.1016/j.tetlet.2012.04.060
日期:2012.7
The reaction of 1-hydroxy-2-alkynylallylphosphonates, synthesized by the addition of the corresponding phosphites to 2-alkynylcinnamaldehydes, under AgOTf or Ph3PAuCl-AgSbF6 catalyzed cycloisomerization afforded 2-furylphosphonates in good to excellent yields. These cyclization reactions were compared with those of 2-alkynylallyl alcohols that led to multisubstituted furans. (C) 2012 Published by Elsevier Ltd.