An efficient synthesis of 2,5-disubstitutedfurans directly from alkynyl ketones has been developed via tandem gold(I)-catalyzed isomerization of alkynyl ketones to allenyl ketones and cycloisomerization. The key to the success of this chemistry is the use of a biphenyl-2-ylphosphine ligand featuring a critical remote tertiary amino group.
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.
Pd(0)-Catalyzed Conjugate Addition of Benzylzinc Chlorides to α,β-Enones in an Atmosphere of Carbon Monoxide: Preparation of 1,4-Diketones
作者:Motoki Yuguchi、Masao Tokuda、Kazuhiko Orito
DOI:10.1021/jo035468+
日期:2004.2.1
Pd(0)-catalyzed conjugate addition of benzylzinc chloride to methyl vinyl ketone in the presence of chlorotrimethylsilane and lithium chloride in an atmosphere of carbon monoxide at room temperature afforded 1-phenyl-2,5-hexanedione monosilyl enol ether. In this catalytic carbonylation, four components are connected in one reaction. Successive acidic workup generated a variety of 1,4-diketones from
m-CPBA-mediated stereoselective synthesis of sulfonyl tetrahydropyrans
作者:Meng-Yang Chang、Yi-Ju Lu、Yu-Chieh Cheng
DOI:10.1016/j.tet.2015.01.016
日期:2015.2
A stereoselective synthesis of sulfonyl tetrahydropyrans (THPs) 6 was performed with moderate to good yields by m-CPBA (m-chloroperoxybenzoic acid)-mediated ring-closure of β-hydroxy sulfones 5. Skeleton 5 is prepared by cinnamylation of β-ketosulfones 3 in the presence of K2CO3 followed by NaBH4-mediated reduction of the resulting skeleton 4 with a α-cinnamyl side arm in the co-solvent of THF and
磺酰基四氢吡喃(THPS)的立体选择性合成6通过与中度至良好的产率进行米-CPBA(米氯过氧酸)介导的闭环β羟基砜5。骨架5是通过在K 2 CO 3存在下将β-酮砜3进行肉桂基化反应,然后在THF和MeOH的共溶剂中用NaBH 4介导的α-肉桂基侧臂还原所得骨架4来制备的。通过X射线晶体学分析证实了骨架6的关键结构。已经讨论了反应机理。
Dual Oxidation State Tandem Catalysis in the Palladium-Catalyzed Isomerization of Alkynyl Epoxides to Furans
作者:Carlos Arroniz、Guilhem Chaubet、Edward A. Anderson
DOI:10.1021/acscatal.8b02248
日期:2018.9.7
states of palladium is described, which mediates the isomerization of alkynyl epoxides to furans. In a process termed “dual oxidation state tandem catalysis”, a multistep isomerization pathway is delineated in which the different metal oxidation states and ligands play independent mechanistic roles, but which, in combination, enable the use of milder reaction conditions and lower catalyst loadings than