Stereoselective Synthesis of (E)-4-Alkylidenecyclopent-2-en-1-ones by a Tandem Ring Closure−Michael Addition−Elimination
摘要:
[GRAPHICS]Reaction of (Z)-1,4-diketones with various functionalized nitroalkanes in the presence of DBU gives 4-alkylidenecyclopent-2-en-1-ones with E selectivity, A cyclopentadienone intermediate is probably formed by intramolecular aldol condensation, and this reacts with a nitroalkane giving a Michael addition-elimination.
A general and efficient synthesis of substituted furans and dihydrofurans via gold-catalyzed cyclization of (Z)-2-en-4-yn-1-ols
作者:Xiangwei Du、Feijie Song、Yuhua Lu、Haoyi Chen、Yuanhong Liu
DOI:10.1016/j.tet.2008.11.109
日期:2009.2
A highlyefficient Au-catalyzed cyclization of (Z)-enynols that proceeds under mild reaction conditions has been developed. This methodology provides rapid access to substituted furans and stereodefined (Z)-5-ylidene-2,5-dihydrofurans in a regioselective manner from suitably substituted (Z)-2-en-4-yn-1-ols.
Indium(III) Chloride Catalyzed Conjugate Addition Reaction of Alkynylsilanes to Acrylate Esters
作者:Yan-li Xu、Ying-ming Pan、Pei Liu、Heng-shan Wang、Xiao-yan Tian、Gui-fa Su
DOI:10.1021/jo202628c
日期:2012.4.6
A novel and efficient procedure for the synthesis of δ,γ-alkynyl esters by the conjugateaddition of alkynylsilanes to acrylate esters in the presence of a catalytic amount of indium(III) chloride has been developed. This method provides a rapid and efficient access to substituted δ,γ-alkynyl esters.
Gold(III)-catalyzed synthesis of 2,5-disubstituted furans from substituted 5-methoxyhex-3-yn-2-ols—Mechanistic outlook
作者:Sagarika Behera、Nabakumar Bera、Debayan Sarkar
DOI:10.1080/00397911.2021.1961274
日期:2021.10.18
alkynes has been applied for the synthesis of 2,5-disubstitutedfurans from substituted 5-methoxy-hex-3-yn-2-ols. Mechanistically, the reaction proceeds via an allenyl carbocation intermediate followed by 5-endo-dig cyclization. The high-yielding, open-air, room temperature reaction conditions applied to synthesize a series of alkyl, aryl, and hetero aryl-substituted furans provide uniqueness to the strategy