The First Method for Protection−Deprotection of the Indole 2,3-π Bond
摘要:
[GRAPHIC]The scope and generality of a new reaction of indoles with MTAD is discussed. In most cases the ene-type reaction proceeds within seconds or minutes at 0 degreesC to provide the urazole adducts in high yield. This reaction provides the first method for protecting the indole 2,3-double bond since the urazole adducts can be reconverted to the starting indole (retro-ene) simply by heating.
作者:Benjamin A. Haag、Zhi-Guang Zhang、Jin-Shan Li、Paul Knochel
DOI:10.1002/anie.201005319
日期:2010.12.3
Updated classic: Primary and secondary alkylzinc reagents add to various aryldiazonium salts leading regioselectively to polyfunctional indoles by means of a [3,3]‐sigmatropic shift and subsequent aromatization. This organometallic variation of the Fischer indolesynthesis tolerates a wide range of functional groups and displays absolute regioselectivity.
A Convenient Modification of the Fischer Indole Synthesis with a Solid Acid
作者:Sosale Chandrasekhar、Somnath Mukherjee
DOI:10.1080/00397911.2014.984854
日期:2015.4.18
the cation exchange resin Amberlite IR 120 in refluxing ethanol. A variety of enolizable aldehydes, and ketones and several substituted phenylhydrazines could thus be converted to the corresponding indoles in excellent yields (70–88%). Reaction times were typically 6–10 h, with the resin being then filtered off and the product isolated after minimal workup. GRAPHICAL ABSTRACT
摘要 标题反应的新一锅版本包括在回流乙醇中加热羰基化合物、苯肼和阳离子交换树脂 Amberlite IR 120 的混合物。因此,各种可烯醇化的醛、酮和几种取代的苯肼可以以极好的收率(70-88%)转化为相应的吲哚。反应时间通常为 6-10 小时,然后将树脂过滤掉,并在最少的后处理后分离产物。图形概要
Iron-Catalyzed Reductive Coupling of Nitroarenes with Olefins: Intermediate of Iron–Nitroso Complex
作者:Heng Song、Zhuoyi Yang、Chen-Ho Tung、Wenguang Wang
DOI:10.1021/acscatal.9b03604
日期:2020.1.3
Using a single half-sandwich iron(II) compound, Cp*Fe(1,2-Ph2PC6H4S)(NCMe) (Cp*– = C5Me5–, 1) as a catalyst, reductivecoupling of nitroarenes with olefins has been achieved by a well-defined iron(II)/(EtO)3SiH system. Through either inter- or intramolecular reductivecoupling, various branched amines and indole derivatives have been directly synthesized in one-pot. Mechanistic studies showed that
使用单一的半夹心铁(II)化合物作为催化剂,将Cp * Fe(1,2-Ph 2 PC 6 H 4 S)(NCMe)(Cp * – = C 5 Me 5 –,1)作为催化剂,进行还原偶联明确定义的铁(II)/(EtO)3 SiH体系可实现硝基芳烃与烯烃的合成。通过分子间或分子内的还原偶联,已经在一锅中直接合成了各种支链胺和吲哚衍生物。机理研究表明,催化作用是由铁(II)催化剂与硅烷活化硝基芳烃而引发的,从而生成用于C-N键偶联的铁-亚硝基芳烃中间体。
Aqueous Titanium Trichloride Promoted Reductive Cyclization of
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‐Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine
TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)–H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β‐disubstituted o‐nitrostyrenes, 2,3‐disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure
heteroarenyne (heteroarene–alkyne) cycloisomerization involving the dearomative transformation of endocyclic aromatic C=C bonds remains unknown. Herein, we communicate a PdH‐catalyzed enantioselective heteroarenyne cycloisomerization reaction of alkyne‐tethered indole substrates (formal 1,5‐ and 1,6‐enynes). Based on this strategy, a variety of structurally diverse chiral spiro and fused indoline derivatives