- Synthesis of Strained γ-Lactams by Palladium(0)-Catalyzed C(sp3)-H Alkenylation and Application to Alkaloid Synthesis
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A variety of strained α-alkylidene-γ-lactams were synthesized by palladium(0)-catalyzed intramolecular C(sp3)-H alkenylation from easily accessible acyclic and monocyclic bromoalkene precursors. These lactams are valuable intermediates for acce
- Holstein, Philipp M.,Dailler, David,Vantourout, Julien,Shaya, Janah,Millet, Anthony,Baudoin, Olivier
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1-Bromo-2,2-dimethylvinyl-lithium (VII) is stable at -110° in THF. On warming to -60° it decomposes to yield tetramethylbutatriene (IX), which in trun reacts with VII to form 1-dimethylvinylidene-2-isopropylidene-3,3-dimethylcyclopropane (XIV), 1,2′-diisopropylidene-1′,1′. 2,2-tetramethyl-dicyclopropylidene (XX), and 1,2,4-triisopropylidene-5,5-dimethyl-spiropentane (XXII) in addition to triisopropylidene-cyclopropane (XV), the first known compound with [3]-radialenestructure. The latter reacts with tetracyanoethylene at room temperature by transient formation of a charge transfer complex to give the spiro compound XXIII instead of a Diels-Alder adduct.
- Koebrich, G,Heinemann, H,Zuendorf, W
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- α-Bromoacrylic Acids as C1 Insertion Units for Palladium-Catalyzed Decarboxylative Synthesis of Diverse Dibenzofulvenes
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Herein α-bromoacrylic acids have been employed as C1 insertion units to achieve the palladium-catalyzed [4 + 1] annulation of 2-iodobiphenyls, which provides an efficient platform for the construction of diverse dibenzofulvenes. This protocol enables the formation of double C(aryl)-C(vinyl) bonds via a C(vinyl)-Br bond cleavage and decarboxylation. It is particularly noteworthy that the method features a broad substrate scope, and various interesting frameworks, such as bridged ring, fused (hetero)aromatic ring, and divinylbenzene, can be successfully incorporated into the products.
- Zhang, Minghao,Deng, Wenbo,Sun, Mingjie,Zhou, Liwei,Deng, Guobo,Liang, Yun,Yang, Yuan
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supporting information
p. 5744 - 5749
(2021/08/18)
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- Practical synthesis of 3-bromo-5,6-dihydropyridin-2-ones via β,γ-unsaturated α-bromo-ketene/imine cycloaddition
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An approach to 3-bromo-4-alkyl-6-aryl-5,6-dihydropyridin-2-ones and 3-bromo-5-ethyl-6-aryl-5,6-dihydropyridin-2-ones starting from β,γ-unsaturated α-bromoketenes and imines is reported. The presence of a bromine atom on the double bond allows performing aziridination or bromine displacement with an amine. The reaction gave fused bicyclic N-allyl-aziridines or 3-amino-substituted 5,6-dihydropyridin-2-ones, depending on the substituents on the six-membered ring.
- Cardillo, Giuliana,Fabbroni, Serena,Gentilucci, Luca,Perciaccante, Rossana,Piccinelli, Fabio,Tolomelli, Alessandra
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p. 5031 - 5040
(2007/10/03)
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- α-Bromo-β,γ-unsaturated ketenes for the synthesis of α-benzylamino-β,γ-unsaturated acids
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The synthesis of α-benzylamino-β,γ-unsaturated acids has been developed starting from α-bromo-α,β-unsaturated chlorides. Via treatment of the acyl chlorides with (R)-pantolactone in the presence of TEA, the in situ formation of the deconjugated ketenes and their direct transformation into chiral esters was performed. The substitution of bromine with benzylamine, followed by acid hydrolysis, allowed to us obtain enantiomerically enriched α-benzylamino-β,γ-unsaturated acids.
- Cardillo, Giuliana,Fabbroni, Serena,Gentilucci, Luca,Perciaccante, Rossana,Tolomelli, Alessandra
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p. 593 - 601
(2007/10/03)
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