Facile Synthesis of Indolelactones Using Mn(III)-Based Oxidative Substitution-Cyclization Reaction
摘要:
Based on the oxidation of indole with Mn(OAc)(3) in the presence of 1,1-diarylethenes affording 3-vinyl-substituted indoles, a similar oxidation using indole-2-carboxylic acids was evaluated in order to effectively introduce the substituent group to the C-3 position of the indolecarboxylic acids. The coupling reaction followed by oxidative cyclization smoothly proceeded at room temperature in an AcOH-HCO2H mixed solvent to give the desired indolelactones in high yields. The reaction details, the structure determination of the products and a brief reaction mechanism are described.
An efficient Br2-catalyzed synthesis of α-(3-indolyl) ketones via dehydrative coupling of simple indoles with acyloins is presented. This reaction proceeded with high C-3 selectivity and a wide substrate scope, and without any metal catalyst. Both the activation of alcohols by carbonyl groups and the catalysis of Br2 were essential. Density functional theory (DFT) calculations indicated that carbonyl
Bismuth nitrate catalyzed condensation reactions of indoline with 1,2‐ and 1,3‐diketones were investigated and were reported to proceed via different reaction pathways with the involvement of one or two of the carbonyl groups. While the reaction of indoline with cyclohexane‐1,3‐dione (4) gave solely condensation product, the reaction between the acetylacetone (5) and indoline provided N‐acetyl indoline
Brønsted Acid-Catalyzed Tandem Pinacol-Type Rearrangement for the Synthesis of α-(3-Indolyl) Ketones by Using α-Hydroxy Aldehydes
作者:Samrat Kundu、Ankush Banerjee、Modhu Sudan Maji
DOI:10.1021/acs.joc.9b02474
日期:2019.12.20
A Brønsted acid-catalyzed pinacol-type rearrangement pathway is reported here to synthesize various substituted α-(3-indolyl) ketones by employing unprotected indoles and α-hydroxy aldehydes as coupling partners. Utilization of economic and readily available Brønsted acid catalyst and use of simple starting precursors exemplify the economic viability of this method. Under this developed protocol, selective
<i>N</i>-Heterocyclic Carbene-Catalyzed Cross-Coupling of Aldehydes with Arylsulfonyl Indoles
作者:Yi Li、Fu-Qiang Shi、Qing-Li He、Shu-Li You
DOI:10.1021/ol9013238
日期:2009.8.6
3-(1-Arylsulfonylalkyl)indoles as electrophiles in the N-heterocyclic carbene-catalyzed umpolung reaction of aldehydes were realized for the first time. This intermolecular Stetter-type reaction features the commercially available catalyst and mild reaction conditions, providing α-(3-indolyl) ketone derivatives in high yields for a wide range of substrates.