科研之友
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摘要
The dual role of amines as both catalysts and substrates for the synthesis of diazo compounds or carboxamides from 1,3-dicarbonyl compounds is described herein. In the presence of a suitable diazo transfer agent, primary and cyclic secondary amines act as basic catalysts for the diazo transfer reaction to malonates, beta-keto esters, and beta-diketones. Depending on the structure of the 1,3-dicarbonyl compound and the nucleophilicity of the amine, the resulting alpha-diazo-beta-keto ester undergoes cleavage of the acyl group to give amides. A multifunctionalized gamma-azido-alpha-diazo-beta-keto ester was cleanly prepared in good yields by this one-pot protocol under practical and safe conditions, being employed in a Knoevenagel-type condensation with aromatic aldehydes to give densely functionalized diazo azido compounds. Further treatment of these unsaturated gamma-azido-alpha-diazo-beta-keto esters with primary amines readily furnished the corresponding alpha-azidocinnamamides in high yields, which were used in the synthesis of novel indole-2-carboxamides through the rhodium-catalyzed intramolecular C-H insertion.
- 出版日期2017-8-3
