Hexafluoroisopropanol as solvent and promotor in the Paal-Knorr synthesis of N-substituted diaryl pyrroles
作者:Robert H.E. Schirmacher、Daniel Rösch、Franziska Thomas
DOI:10.1016/j.tet.2021.131985
日期:2021.3
An additive-free synthesis of challenging N-substituted aryl pyrrolesfrom the often poorly soluble corresponding 1,4-diketones by means of the Paal-Knorr pyrrole synthesis is reported, which makes use of the unique properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction promotor. Our procedure offers simple execution and purification as well as easy scale-up and can be applied
A LiBr-promoted formal C(sp3)–H bond insertionreaction between β-carbonyl esters and sulfoxoniumylides is established. This practical reaction has a wide range of substrate scope for both β-carbonyl esters and sulfoxoniumylides to give a variety of 1,4-dicarbonyl compounds with 43–94% yields. The reaction features transition-metal-free reaction conditions and exclusive C-alkylation chemselectivity
An efficient manganese oxide octahedral molecular sieves OMS-2-catalyzed chemoselective synthesis of 1,4-enediones and 1,4-diketones from 1,3-dicarbonyls and alpha-iodoacetophenones is described. The present catalytic system can be applied in one-pot, three-component reactions of methyl ketones, 1,3-dicarbonyls and iodine. Moreover, OMS-2 can be reused at least 5 times without loss of activity. (C) 2015 Elsevier B.V. All rights reserved.
Trebaul,C.; Teste,J., Bulletin de la Societe Chimique de France, 1970, p. 2272 - 2277