functionalized quinolines and pyridines could be synthesized by BF3⋅OEt2‐mediated reactions of vinylazides with N‐aryl and N‐alkenyl aldimines, respectively. The reaction mechanism could be characterized as formal [4+2]‐annulation, including unprecedented enamine‐type nucleophilic attack of vinylazides to aldimines and subsequent nucleophilic cyclization onto the resulting iminodiazonium ion moieties.
The synthetic utility of tert-butyl azidoacetate (7) on the Hemetsberger-Knittel reaction is described. The following two findings are disclosed by using tert-butyl azidoacetate (7) : i) in the first step for the synthesis of ethyl indole-2-carboxylate 4, the aldol reaction of less reactive aldehydes 1a, b was improved greatly; ii) tert-butyl indole-2-carboxylate 10 becomes readily available from aldehydes.
pyrrole formation by the reaction of vinylazides with 1,3-dicarbonyl compounds via the 1,2-addition of 1,3-dicarbonyl compounds to 2H-azirine intermediates generated in situ from vinylazides; (ii) the Cu(II)-catalyzed synthesis of pyrroles from alpha-ethoxycarbonyl vinylazides and ethyl acetoacetate through the 1,4-addition reaction of the acetoacetate to the vinylazides. By applying these two methods
Visible-Light-Mediated Synthesis of Pyrazines from Vinyl Azides Utilizing a Photocascade Process
作者:Asik Hossain、Santosh Pagire、Oliver Reiser
DOI:10.1055/s-0036-1590888
日期:2017.9
A convenient method for the synthesis of substituted pyrazines from vinylazides has been developed. This method is enabled by a dual-energy and electron-transfer strategy by visible-lightphotocatalysis. Initially, vinylazides are activated by a triplet sensitization process from an excited ruthenium photocatalyst in the presence of water to form dihydropyrazines, followed by a single-electron-transfer
A Tandem Approach to Isoquinolines from 2-Azido-3-arylacrylates and α-Diazocarbonyl Compounds
作者:Yun-Yun Yang、Wang-Ge Shou、Zheng-Bo Chen、Deng Hong、Yan-Guang Wang
DOI:10.1021/jo8003259
日期:2008.5.1
2-Azido-3-arylacrylates react with α-diazocarbonyl compounds and triphenylphosphine to furnish isoquinolines in 60−92% yields. The tandem process involves a Wolff rearrangement, an aza-Wittig reaction, and an electrocyclic ringclosure. The procedure is efficient, rapid, and general, and the substrates are readily available.