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Start Over Author "Prandi, Cristina" Journal european journal of organic chemistry
18 results on '"Prandi, Cristina"'

5. Gold(I)‐Catalysed Hydroarylation of Lactam‐Derived Enynes as an Entry to Tetrahydrobenzo[g]quinolines.

Author

Nejrotti, Stefano, Ghinato, Simone, Gini, Elena C., Scarpi, Dina, Occhiato, Ernesto G., Maranzana, Andrea, and Prandi, Cristina

Subjects
ENYNES, DOUBLE bonds
Abstract

The gold(I)‐catalysed cyclization of N‐tosyl‐protected 5‐benzyl‐6‐((trimethylsilyl)ethynyl)‐1,2,3,4‐tetrahydropyridines, prepared by the Sonogashira coupling of lactam‐derived enol triflates, provides tetrahydrobenzo[g]quinolines whose skeleton represents a recurrent motif in natural compounds. The Au(I)‐catalysed reaction is carried out with (C6F5)3PAuCl/AgNTf2 as the catalyst system and proceeds via a 6‐exo‐dig cyclization to form an exocyclic double bond, which eventually isomerises to the aromatic tetrahydrobenzo[g]quinoline. The mode of cyclization is discussed and supported by DFT calculations. [ABSTRACT FROM AUTHOR]

Published
2020
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12. Gold-Catalysed Synthesis of Exocyclic Vinylogous Amides and β-Amino Ketones: A Detailed Study on the 5-exo/6-endo-dig Selectivity, Methodology and Scope.

Author

Scarpi, Dina, Begliomini, Stefano, Prandi, Cristina, Oppedisano, Alberto, Deagostino, Annamaria, Gómez-Bengoa, Enrique, Fiser, Béla, and Occhiato, Ernesto G.

Subjects
GOLD, AMIDES, PYRIDINE, ALKYNES, KETONES
Abstract

The gold(I)-catalysed reaction of N-Boc-protected 6-alkynyl- 3,4-dihydro-2H-pyridines, which gives synthetically useful vinylogous amides (β-enaminones), has been studied in detail, in order to optimize the reaction conditions, enlarge the scope and gain insight into the mechanism and the structural features that selectively favour the 6-endo-dig oxyauration of the triple bond. Experimental studies and DFT calculations demonstrate that the 6-endo-dig approach is exclusive with substituted alkynes, whereas with terminal alkynes the 5- exo-dig cyclization prevails, despite the large angle (120°) at C-6. The same selectivity was observed with N-Cbz-protected 2-alkynylpiperidines. With these compounds, β-amino ketones are obtained as a consequence of the 6-endo-dig attack onto a substituted triple bond. Sedamine alkaloids are easily obtained by this approach. [ABSTRACT FROM AUTHOR]

Published
2015
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17. Mixed Superbase LICKOR as a Key Reagent for the Synthesis of Conjugate Dienes from Citral and Farnesal – A New Route to a Potential Mimic Agent of Juvenile Hormones by Diels–Alder Cycloaddition

Author

Tivola, Paolo Balma, Deagostino, Annamaria, Fenoglio, Claudia, Mella, Mariella, and Prandi, Cristina

Abstract

Treatment of the dimethyl acetals of citral (1) and farnesal (2) with the superbase “LICKOR” in THF at low temperatures induces regioselective metallation at the allylic methyl group at C(3). The metal–hydrogen exchange promotes immediate 1,4-elimination, yielding an (E)-configured conjugate alkyloxy-functionalized diene. The elimination product can be subjected to a Diels–Alder reaction, which allows further synthetic elaboration. In particular, in the case of farnesal dimethyl acetal the cycloaddition process leads to a derivative that can be transformed into a potential mimic agent of Juvenile hormones.

Published
1999
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18. Front Cover: Gold(I)‐Catalysed Hydroarylation of Lactam‐Derived Enynes as an Entry to Tetrahydrobenzo[g]quinolines (Eur. J. Org. Chem. 6/2020).

Author

Nejrotti, Stefano, Ghinato, Simone, Gini, Elena C., Scarpi, Dina, Occhiato, Ernesto G., Maranzana, Andrea, and Prandi, Cristina

Subjects
ENYNES, QUINOLINE, FRUIT trees
Abstract

Front Cover: Gold(I)-Catalysed Hydroarylation of Lactam-Derived Enynes as an Entry to Tetrahydrobenzo[g]quinolines (Eur. J. Org. The fruit represents tetrahydrobenzo[ I g i ]quinolines, and the chemist is going to add it to other fruits he has already collected from the -valerolactam tree. Indeed, the gold-catalysed synthesis of tetrahydrobenzo[ I g i ]quinolines enlarges the palette of molecular scaffolds accessible in few steps from the same simple lactam precursor. [Extracted from the article]

Published
2020
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