Ambivalent role of metal chlorides in ring opening reactions of 2H-azirines: synthesis of imidazoles, pyrroles and pyrrolinones
作者:Sergio Auricchio、Ada M. Truscello、Mirvana Lauria、Stefano V. Meille
DOI:10.1016/j.tet.2012.06.069
日期:2012.9
the presence of metal salts. Imidazoles, pyrroles and new pyrrolinones derivatives are isolated in good overall yields. The role of metal salts was investigated as they can act as Lewis acids or electron donors. Mechanisms are proposed suggesting that imidazoles arise from addition of azirine to imines via radical or ionic mechanism; pyrroles and pyrrolinones are obtained from azirines with enamino
Domino transformation of isoxazoles to 2,4-dicarbonylpyrroles under Fe/Ni relay catalysis
作者:Ekaterina E. Galenko、Alexey V. Galenko、Alexander F. Khlebnikov、Mikhail S. Novikov
DOI:10.1039/c5ra01889g
日期:——
The domino reaction of 5-alkoxy- or 5-aminoisoxazoles, under metal relay catalysis, with symmetric 1,3-diketones gives 4-acylpyrrole-2-carboxylic acid derivatives in high yield.
Tetrasubstituted N−H pyrroles were accessed through the tandem copper(II)-catalyzed 1,3-dipolarcycloaddition of α,β-ynones and glycine iminoesters, followed by a copper(II)-promoted oxidative dehydrogenative aromatization reaction in air. Fully substituted pyrroles could then be obtained by N-alkylation.
(lamellarin R, lukianol A and lamellarin O) were synthesized using the Barton–Zard reaction as a key step to construct the central pyrrole core. Some of their corresponding 4-benzoyl and 5-phenyl substituted pyrrole analogues were also prepared via an initial three-componentreaction of glycine methyl ester, benzaldehyde, and chalcone to generate the pyrrolidine scaffold, and followed by DDQ oxidation
使用 Barton-Zard 反应作为构建中心吡咯核心的关键步骤,合成了三种 III 型片层生物碱(片层素 R、lukianol A 和片层素 O)。一些相应的4-苯甲酰基和5-苯基取代的吡咯类似物也通过甘氨酸甲酯、苯甲醛和查尔酮的初始三组分反应生成吡咯烷支架,然后进行DDQ氧化和N-烷基化来制备。