Carbonylation of Alkynyl Epoxides: Synthesis of 5-Hydroxy-2,3-dienoate Esters and 2,3-Dihydrofuran-3-ol Derivatives
摘要:
The carbonylation of alkynyl oxiranes catalyzed by (MePh2)(4)Pd in the presence of 20 atm of carbon monoxide in methanol gives methyl 5-hydroxy-2,3-pentadienoates in good yields. When the reaction is performed on alkynyl oxiranemethanol derivatives, 4,5-dihydrofuran-3-ol derivatives are obtained stereoselectively. These products arise from the spontaneous cyclization of a dihydroxyallenyl ester intermediate.
Simultaneous Synthesis of Both Rings of Chromenes via a Benzannulation/<i>o</i>-Quinone Methide Formation/Electrocyclization Cascade
作者:Nilanjana Majumdar、Keith A. Korthals、William D. Wulff
DOI:10.1021/ja210655g
日期:2012.1.18
A new route to the chromene ring system has been developed which involves the reaction of an α,β-unsaturated Fischer carbenecomplex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon. This transformation involves a cascade of reactions that begins with a benzannulation reaction and is followed by the formation of an o-quinone methide, and finally results in the emergence
开发了一种色烯环体系的新路线,该路线涉及铬的α,β-不饱和费歇尔卡宾络合物与在炔丙碳上带有烯基的炔丙醚的反应。这种转化涉及一系列反应,从苯并环化反应开始,然后形成邻醌甲基化物,最后在电环化时产生色烯。通过使用芳基卡宾络合物,该反应被扩展以提供通路。这是色烯的首次合成,其中色烯系统的两个环均在一步中生成,并在 lapachenole 和维生素 E 的合成中得到突出体现。
Ruthenium-catalyzed formation of pyrazoles or 3-hydroxynitriles from propargyl alcohols and hydrazines
作者:Julia Kaufmann、Elisabeth Jäckel、Edgar Haak
DOI:10.24820/ark.5550190.p010.893
日期:——
Functionalized pyrazoles are generated from secondary propragyl alcohols and hydrazines in a rutheniumcatalyzed cascade process, consisting of redox isomerization, Michael addition, cyclocondensation and dehydrogenation steps. The same bifunctional catalyst mediates the conversion of tertiary propargyl alcohols with hydrazine to 3-hydroxynitriles via anti-Markovnikov hydroamination followed by elimination
On the [2,3]-sigmatropic rearrangements of sulfenate esters derived from alkenynols: synthesis of vinylallene and vinylacetylene sulfoxides.
作者:Eugène M.G.A. van Kruchten、William H. Okamura
DOI:10.1016/s0040-4039(00)87011-2
日期:1982.1
The reactions of various alkenynols with phenylsulfenyl chloride result in the formation of either vinylallene sulfoxides or vnylacetylene sulfoxides, depending on the substitution pattern of the starting material.
The first copper-catalyzed imidovinylation of alkynes has been developed, which grants facile access to various (E)-2-imido-2,4-dienals with high stereoselectivity under mild conditions. This transformation also represents the first 1,3-carbon migration of propargylic alcohols and their derivatives.
Synthesis of Pyranocyclopentaindolines Representing the Western Sections of Janthitrem B, JBIR‐137, and Shearinine G
作者:Marvin Fresia、Thomas Lindel
DOI:10.1002/ejoc.202101454
日期:2022.5.6
A set of pyranocyclopentaindolines: Tetracycles representing the ABCD partial structures of the fungal indole diterpenes janthitrem B, JBIR-137, and shearinine G were synthesized starting from indoline. The hydroxylated western section of janthitrem B was obtained in eight steps and 10 % overall yield.
一组吡喃环戊二烯:代表真菌吲哚二萜类 janthitrem B、JBIR-137 和舍利宁 G 的 ABCD 部分结构的四环化合物是从二氢吲哚开始合成的。janthitrem B 的羟基化西部切片分 8 步获得,总产率为 10%。