The Evolution of Fe‐catalyzed Nucleophilic Activation of Acceptor‐substituted Vinyl‐ and Arylcyclopropanes

Lin, Che‐Hung; Plietker, Bernd

doi:10.1002/ijch.201500085

Cited by 14 publications

(3 citation statements)

References 85 publications

(29 reference statements)

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“…As manifest in the examples shown in Scheme 2, CÀCb onds can be cleaved analogously. [38][39][40][41] Specifically,e nyne 20 was convertedi nto diene 21 in good yield by an overall process in which two CÀCb onds are formed while another CÀ Cb ond is concomitantly broken;c hanging the alkyl-Grignard reagentd id not affect the course (20!23). Once again,t he transformationt urned out to be highly regio-and stereoselective with regard to the newly formed tetrasubstituted alkene.…”

Section: Iron-catalyzed Cascades Involving Càcb Ond Cleavagementioning

confidence: 99%

Iron‐ or Palladium‐Catalyzed Reaction Cascades Merging Cycloisomerization and Cross‐Coupling Chemistry

Gomes

Echeverria

Fürstner

2018

Chemistry A European J

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A conceptually novel reaction cascade is presented, which allows readily available enynes to be converted into functionalized 1,3-dienes comprising a stereodefined tetrasubstituted alkene unit; such compounds are difficult to make by conventional means. The overall transformation is thought to commence with formation of a metallacyclic intermediate that evolves via cleavage of an unstrained C-X bond in its backbone. This non-canonical cycloisomerization process is followed by a cross-coupling step, such that reductive C-C bond formation regenerates the necessary low-valent metal fragment and hence closes an intricate catalytic cycle. The cascade entails the formation of two new C-C bonds at the expense of the constitutional C-X entity of the substrate: importantly, the extruded group X must not be a heteroelement (X=O, NR), since activated β-C-C bonds can also be broken. This concern was reduced to practice in two largely complementary formats: one procedure relies on the use of alkyl-Grignard reagents in combination with catalytic amounts of Fe(acac) whereas the second method amalgamates cycloisomerization with Suzuki coupling by recourse to arylboronic acids and phosphine-ligated palladium catalysts.

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Section: Iron-catalyzed Cascades Involving Càcb Ond Cleavagementioning

confidence: 99%

Iron‐ or Palladium‐Catalyzed Reaction Cascades Merging Cycloisomerization and Cross‐Coupling Chemistry

Gomes

Echeverria

Fürstner

2018

Chemistry A European J

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“…Recently, our group developed an iron-catalyzed carbene transfer reaction to isocyanides for the construction of multiple heterocycles . The ferrate complex, Bu 4 N[Fe(CO) 3 NO] (also known as the Hieber anion), was demonstrated to effectively catalyze the transfer of carbenes to isocyanides to give a ketenimine intermediate. In this work, we demonstrate for the first time that the Hieber anion can be employed to catalyze a dearomative spirocyclization of 3-(2-isocyanoethyl)indoles ( 1 ).…”

Section: Introductionmentioning

confidence: 99%

Dearomative Spirocyclization of Tryptamine-Derived Isocyanides via Iron-Catalyzed Carbene Transfer

Roose,

McSorley,

Groenhuijzen

et al. 2023

J. Org. Chem.

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Tryptamine-derived isocyanides are valuable building blocks in the construction of spirocyclic indolenines and indolines via dearomatization of the indole moiety. We report the Bu 4 N[Fe(CO) 3 NO]-catalyzed carbene transfer of α-diazo esters to 3-(2-isocyanoethyl)indoles, leading to ketenimine intermediates that undergo spontaneous dearomative spirocyclization. The utility of this iron-catalyzed carbene transfer/spirocyclization cascade was demonstrated by its use as a key step in the formal total synthesis of monoterpenoid indole alkaloids (±)-aspidofractinine, (±)-limaspermidine, (±)-aspidospermidine, and (±)-17-demethoxy- N -acetylcylindrocarine.

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“…Notably, DA cyclopropanes are known to undergo a variety of ring enlargement processes. In particular, Cloke–Wilson rearrangement of cyclopropyl carbonyls and imines, cyclopropanecarboxylate lactonization, and related processes can produce five-membered heterocycles . The homo-Nazarov rearrangement and related reactions can form six-membered rings .…”

Section: Introductionmentioning

confidence: 99%

Expanding Stereoelectronic Limits of endo-tet Cyclizations: Synthesis of Benz[b]azepines from Donor–Acceptor Cyclopropanes

et al. 2021

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The importance of intramolecular constraints in cyclic transition-state geometries is especially pronounced in nendo-tet cyclizations, where the usual backside approach of a nucleophile to the breaking bond is impossible for the rings containing less than eight atoms. Herein, we expand the limits of endo-tet cyclizations and show that donor−acceptor cyclopropanes can provide a seven-membered ring via a genuine 6-endo-tet process. Substrates containing a N-alkyl-N-arylcarbamoyl moiety as an acceptor group undergo Lewis acid-induced cyclization to form tetrahydrobenz[b]azepin-2-ones in high yields. The reaction proceeds with the inversion of the configuration at the electrophilic carbon. In this process, a formally six-membered transition state yields a seven-membered ring as the pre-existing cycle is merged into the forming ring. The stereochemistry of the products can be controlled by the reaction time and by the nature of Lewis acid, opening access to both diastereomers by tuning of the reaction conditions.

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The Evolution of Fe‐catalyzed Nucleophilic Activation of Acceptor‐substituted Vinyl‐ and Arylcyclopropanes

Cited by 14 publications

References 85 publications

Iron‐ or Palladium‐Catalyzed Reaction Cascades Merging Cycloisomerization and Cross‐Coupling Chemistry

Iron‐ or Palladium‐Catalyzed Reaction Cascades Merging Cycloisomerization and Cross‐Coupling Chemistry

Dearomative Spirocyclization of Tryptamine-Derived Isocyanides via Iron-Catalyzed Carbene Transfer

Expanding Stereoelectronic Limits of endo-tet Cyclizations: Synthesis of Benz[b]azepines from Donor–Acceptor Cyclopropanes

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