Preparation of Polyfunctional Aryl Azides from Aryl Triazenes. A New Synthesis of Ellipticine, 9-Methoxyellipticine, Isoellipticine, and 7-Carbethoxyisoellipticine
摘要:
[GRAPHICS]The preparation of polyfunctional aryl azides by the reaction of aryl triazenes with NaN3 in the presence of KHSO4 or BF3 center dot OEt2/TFA (trifluoroacetic acid) has been described. A variety of functional groups (halides, esters, ketones, nitriles, aldehydes, and boronic esters) are tolerated under the Lewis acidic conditions. By using this methodology, the potent antitumor agents, ellipticine and 9-methoxyellipticine, have been synthesized. In addition, isoellipticine and a related derivative, 7-carbethoxyisoellipticine, were also prepared.
A copper-free allylic arylation reaction between 3,3-disubstituted allylic halides and triazene-softened aryl Grignard reagents has been developed.
一种无铜的3,3-二取代烯丙基卤化物与三氮烯软化芳基格氏试剂之间的烯丙基芳基化反应已经开发出来。
General and Efficient Synthesis of Indoles through Triazene-Directed C-H Annulation
作者:Chengming Wang、Huan Sun、Yan Fang、Yong Huang
DOI:10.1002/anie.201301742
日期:2013.5.27
Unprotected indoles are prepared with the title method, which has a wide scope for alkynes. Excellent regioselectivity was accomplished for aryl–alkyl and alkyl–alkyl disubstituted acetylenes. This reaction features an unusual 1,2 rhodium migration and ring‐contraction‐triggered NN bond cleavage. It allows rapid conversion of the reaction products into several functional molecules.
A new approach to the synthesis of 2 H‐benzotriazoles is described. This strategy is based on the copper‐catalyzed CN coupling of 2‐haloaryltriazenes or 2‐haloazo compounds with sodium azide and the intramolecular addition of nitrene to NN bonds. This approach allows the synthesis of various N‐amino‐ and N‐aryl‐2 H‐benzotriazoles in water, in good to excellent yields. The procedure is simple and
Efficient copper mediated arylation of sugar thiols by o-haloaryl triazenes under mild conditions is described. The developed method allows the preparation of symmetrical and unsymmetrical 1,3-bis(glycopyranosylthio)benzene derivatives.
cross-coupling with an intramolecular cyclization strategy. 1H NMR studies of these macrocycles and comparison with related systemsverify that highly alkynylated dehydrobenzoannulenes possess weak inducedringcurrents, indicative of aromatic (4n+2 π-systems) and anti-aromatic (4n π-systems) behavior, in spite of their large size and extensive benzannulation.