Akzeptoren für die doppelte Michael-reaktion, eine verbesserte synthese von cyclopropylidencarbonsäureestern und deren reaktivität gegenüber cyclohexadienolaten

Spitzner, D.; Swoboda, H.

doi:10.1016/s0040-4039(00)84238-0

Cited by 50 publications

(8 citation statements)

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“…The reac- tions of azabromodienes 2aϪf with dienophiles like methyl and tert-butyl acrylate (5a and b), di-tert-butyl maleate (5c), acrylonitriles 5d,e also followed an analogous course to give the corresponding N-protected tetrahydroisoindolines 6acϪfe in moderate to good yields (Entries 2Ϫ17, Table 1). Similarly, the treatment of 2aϪc and 2e with cyclopropylideneacetates 5f,g [12,13] under identical reaction conditions afforded the tricyclic adducts 6afϪeg in 41Ϫ69% overall yields (Entries 18Ϫ22, Table 1 and Scheme 2). Consistently, the cycloadducts containing N-Boc as well as N-benzyl groups were obtained in lower yields than those with Nacetyl and N-formyl groups.…”

Section: Introductionmentioning

confidence: 97%

Convenient Synthesis of Heterobicycles by Domino Heck−Diels−Alder Reactions

et al. 2001

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Keywords: Heck reaction, intramolecular / DielsϪAlder reaction / Tetrahydroisoindolines / Tetrahydroisoindolin-1-ones / Hexahydrobenzo[c]furans / Hexahydro-1H-[2]pyrindines Palladium(0)-catalyzed intramolecular cross coupling of bromodialkenylamines, bromoalkenylalkenamides and bromodialkenyl ethers followed by in situ [4+2] cycloaddition with suitable dienophiles gave tetrahydroisoindolines (31−73%

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Section: Introductionmentioning

confidence: 97%

Convenient Synthesis of Heterobicycles by Domino Heck−Diels−Alder Reactions

et al. 2001

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“…The wide and diversified application of these compounds in organic synthesis is well documented in comprehensive reviews which recently appeared . Among the functionally substituted substrates in this family, the cyclopropylideneacetates 1 with an alkoxycarbonyl group at the exocyclic carbon−carbon double bond can easily be obtained by acid-catalyzed Wittig olefination of the cyclopropanone hemiacetal …”

Section: Introductionmentioning

confidence: 99%

Chameleon Thermal Behavior of Cycloadducts of Nitrones to Methyl 2-Chloro-2-cyclopropylidene- and 2-Chloro-2-spiropentylideneacetates

et al. 1999

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Methyl 2-chloro-2-cyclopropylideneacetate (2) and its spiropentane analogue 3 cycloadd to dihydroisoquinoline N-oxide (9), pyrroline N-oxide (12), and C-phenyl-N-methylnitrone (16) to give 5-spirocyclopropaneisoxazolidines in good yields (58-93%). The thermal behavior of the 5-spirocyclopropaneisoxazolidines is rather differentiated, depending strongly on the constitution of the nitrone and the solvent. As nitrone 9 has the tendency to undergo cycloreversion reactions, the ketoamide rearrangement products 20 and 21 from its cycloadduct derive from the thermodynamically favored 4-spirocyclopropaneisoxazolidine regioisomers formed after the cycloreversion process. In DMSO as solvent different rearrangement processes take place, leading to benzoindolizinones in modest yields (15-21%). The cycloadducts from 12 and 16 undergo a cyclopropyl to cyclobutyl ring enlargement facilitated by the presence of a chlorine substituent on the carbon alpha to the spirocyclopropane ring. Whereas these compounds from nitrone 16 demonstrated an unusual stability, those from nitrone 12 undergo a cascade rearrangement to yield indolizinone derivatives 34, 35 cleanly (73-83% yield). This overall transformation offers a new method for the synthesis of the indolizine skeleton.

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“…The methylenecyclopropane 2d , 2e , 2f , 2g , 2h , 2i , 2j , and 2k were prepared according to literature methods, and their spectral data matched literature values.…”

Section: Methodsmentioning

confidence: 99%

Cycloaddition of Fluorenone N-Aryl Nitrones with Methylenecyclopropanes and Sequential 1,3-Rearrangement: An Entry to Synthesis of Spirofluorenylpiperidin-4-ones

Zhu

et al. 2016

J. Org. Chem.

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A facile synthesis of various spirofluorenylpiperidin-4-ones has been achieved in good yields from fluorenone N-aryl nitrones and methylenecyclopropanes. This method involved an initial cycloaddition to form a 5-spirocyclopropane-isoxazoline, which underwent a highly selective 1,3-rearrangement to give the desired product. The stereochemistry of the spirofluorenylpiperidin-4-one could be controlled by the cycloaddition and sequential rearrangement strategy. Furthermore, the spirofluorenylpiperidin-4-ones could be not only prepared in one-pot procedure but also converted to useful scaffolds by reduction or oxidation conditions.

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Akzeptoren für die doppelte Michael-reaktion, eine verbesserte synthese von cyclopropylidencarbonsäureestern und deren reaktivität gegenüber cyclohexadienolaten

Cited by 50 publications

References 10 publications

Convenient Synthesis of Heterobicycles by Domino Heck−Diels−Alder Reactions

Convenient Synthesis of Heterobicycles by Domino Heck−Diels−Alder Reactions

Chameleon Thermal Behavior of Cycloadducts of Nitrones to Methyl 2-Chloro-2-cyclopropylidene- and 2-Chloro-2-spiropentylideneacetates

Cycloaddition of Fluorenone N-Aryl Nitrones with Methylenecyclopropanes and Sequential 1,3-Rearrangement: An Entry to Synthesis of Spirofluorenylpiperidin-4-ones

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