1,5-Diarylpent-4-ene-1,3-diones in the synthesis of spiro[(thia)pyrrolizidine-3,3'-oxindoles] and 1,3-diaryl-5-spiro[oxindole-3,3'-pyrrolizidin-2'-yl]-1H-pyrazoles

Decarboxylative 1,3-dipolar cycloadditions of l-proline

“…At the same time, by using azomethine ylides in the reaction with enediones 21, Korotaev et al could provide spiro-oxindolopyrrolizidine derivatives 22, 23 ( Scheme 9 ). 41 Afterward, the treatment of the tetracyclic products with arylhydrazine hydrochloride reagents 24 led to 5-substituted 1,3-diaryl-1 H -pyrazole skeletons 25 in moderate to excellent yields.…”

Hemicurcuminoids (1-styryl-1,3-diketones) – valuable multi-faceted building blocks for organic synthesis

“…Our group has found that in addition to the abovementioned properties, diarylpentenediones 1 are also effective dipolarophiles in the [3+2]-cycloaddition. It was shown that reactions with stabilized azomethine ylides obtained from indeno[1,2- b ]quinoxaline-11-one, 132 isatins, 133 acenaphthenequinone 134 and cyclic amino acids proceed regio- and diastereoselectively under mild conditions and lead to a wide range of spiroadducts with high yields. Using the example of products 118 and 121 we have demonstrated that the 1,3-dicarbonyl fragment could be subjected to heterocyclisation with hydrazines and hydroxylamine.…”