Catalytic [3+2] Annulation of Aminocyclopropanes for the Enantiospecific Synthesis of Cyclopentylamines

Nanteuil, Florian de; Waser, Jérôme

doi:10.1002/ange.201106255

Cited by 62 publications

(11 citation statements)

References 86 publications

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“…To prevent this unwanted side reaction, supplementary addition of a bisoxazoline/Zn II complex was necessary (Table 6, entry 1) 59. A similar ring opening was also observed in the reaction of aminocyclopropanes with silyl enol ethers, in which the use of SnCl 4 as a catalyst gave the best yields of the desired aminocyclopentanes 57 b (Table 6, entry 2) 60. A high steric demand of the acceptor substituent as well as of the silyl groups turned out to be the determining factors for further improving the diastereoselectivities of these transformations.…”

Section: Cycloadditionsmentioning

confidence: 76%

A New Golden Age for Donor–Acceptor Cyclopropanes

2014

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The effective use of ring strain has been applied to considerable advantage for the construction of complex systems. The focus here is directed towards cyclopropanes as building blocks for organic synthesis. Although thermodynamics should take the side of synthetic chemists, only a specific substitution pattern at the cyclopropane ring allows for particularly mild, efficient, and selective transformations. The required decrease in the activation barrier is achieved by the combined effects of vicinal electron-donating and electron-accepting moieties. This Review highlights the appropriate tools for successfully employing donor-acceptor cyclopropanes in ring-opening reactions, cycloadditions, and rearrangements.

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Section: Cycloadditionsmentioning

confidence: 76%

A New Golden Age for Donor–Acceptor Cyclopropanes

2014

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“…2). [60] Um noch bessere Diastereoselektivitäten zu erreichen, war hierbei ein hoher sterischer Anspruch sowohl der Akzeptor-Substituenten als auch der Silyl-Gruppen ausschlaggebend. Diese Beobachtung führte in Kombination mit DFT-Rechnungen bei Qu und Mitarbeitern zu der Annahme, dass es sich bei dieser formalen [3+2]-Cycloaddition um eine schrittweise ablaufende Reaktion handelt, bei der der zweite Schritt, die intramolekulare Cyclisierung, geschwindigkeitsbestim-mend ist.…”

Section: Cycloadditionen Mit Enen Allenen Und Dienenunclassified

Ein neues goldenes Zeitalter in der Chemie Donor‐Akzeptor‐substituierter Cyclopropane

2014

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95 %, -, 90 % ee [b] [a] Aryl = H/Cl/Br/OMe/NO 2 -Ph, 1-Naphthyl, Styryl; R = o/p-OMe, m-NHBoc, m-Cl, o-Br, p-CF 3 ; R' = H, Alk, H; R'' = Me, Ph, Bn, Allyl; Bn = Benzyl, Boc = tert-Butoxycarbonyl, Nu = Nukleophil, LA = Lewis-Säure. [b] Einsatz enantiomerenreiner Dreiringverbindungen. [c] In situ durch NaN 3 und NH 4 Cl. Donor-Akzeptor-substituierte Cyclopropane Angewandte Chemie 5611 Schema 11. a) Aufbau von Bicyclen des Typs 45; b) intramolekulare Ringerweiterung von gem-Carbonyl-Alkinyl-Cyclopropanen 44 c. Schema 12. Formale [8+3]-Cycloaddition von D-A-Cyclopropanen mit Tropon-Derivaten 48.

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“…The reactions can be performed with triazenes derived from aliphatic as well as aromatic alkynes, and variations of the dialkylamine part are also possible. [15] However, the use of versatile aminocyclopropanes [16] as reaction partners were not reported in this work. We were able to obtain the cyclopentene derivatives 18 (yield: 42%) and 19 (yield: 80%) by reaction of 1-alkynyltriazenes with an aminocyclopropane (Scheme 65).…”

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confidence: 94%