A mild synthetic protocol to access 2-ester pyrroles through Cu(OTf)2-catalysed carbene insertion/ester migration/cyclization of enaminones and α-diazo compounds is reported.
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
Solvent-Free Thermal and Microwave-Assisted [3 + 2] Cycloadditions between Stabilized Azomethine Ylides and Nitrostyrenes. An Experimental and Theoretical Study
作者:Ana Arrieta、Dorleta Otaegui、Aizpea Zubia、Fernando P. Cossío、Angel Díaz-Ortiz、Antonio de la Hoz、M. Antonia Herrero、Pilar Prieto、Concepción Foces-Foces、José L. Pizarro、María I. Arriortua
DOI:10.1021/jo062672z
日期:2007.6.1
[3 + 2] cycloadditionbetween stabilized azomethine ylides and nitrostyrenes have been analyzed using experimental and computational approaches. It has been observed that, in the absence of solvent, three stereoisomers are formed, both under classical heating conditions and under microwave irradiation. This result contrasts with that observed in solution under classical thermal conditions. The 4-nitropyrrolidines