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Kitagawa, Osamu; Yamada, Yoichiro; Fujiwara, Hirokazu; Taguchi, Takeo

doi:10.1002/1521-3757(20011015)113:20<3983::aid-ange3983>3.3.co;2-i

Cited by 4 publications

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“…30 In previous work we described the efficient synthesis of iodo-BCPs by atom transfer radical addition (ATRA) of alkyl and (hetero)aryl iodides to the C1−C3 bond of 1 31,32 and questioned whether this approach could be applied to the synthesis of BCPAs. We recognized that N-centered radicals can be conveniently accessed by fragmentation of αiodoaziridines (2, Figure 1c) 33,34 and hypothesized that 1 could serve as a suitable radical acceptor, with the resulting BCP radical then abstracting an iodine atom from the αiodoaziridine starting material. The C−I bond resident in the iodo-BCPA product 3 would then provide a handle for further functionalization, potentially via reformation of a BCP radical.…”

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confidence: 99%

“…37 α-Iodoaziridine 2a was selected for reaction optimization (Table 1). Based on the studies of Taguchi 33,34 and our experience with the addition of C-centered radicals to 1, 31,32 triethylborane was first tested as an initiator. Pleasingly, the desired C−N σ bond fragmentation/ATRA proceeded efficiently using 2.0 equiv of 1, giving iodo-BCP sulfonamide 3a in 67% yield (entry 1); small amounts of staffane 3a-S, Hatom abstraction product 3a-H, and N-allylsulfonamide 5a were also observed.…”

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Twofold Radical-Based Synthesis of N,C-Difunctionalized Bicyclo[1.1.1]pentanes

et al. 2021

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Bicyclo[1.1.1]pentylamines (BCPAs) are of growing importance to the pharmaceutical industry as sp 3 -rich bioisosteres of anilines and N-tert-butyl groups. Here we report a facile synthesis of 1,3-disubstituted BCPAs using a twofold radical functionalization strategy. Sulfonamidyl radicals, generated through fragmentation of α-iodoaziridines, undergo initial addition to [1.1.1]propellane to afford iodo-BCPAs; the newly formed C−I bond in these products is then functionalized via a silyl-mediated Giese reaction. This chemistry also translates smoothly to 1,3-disubstituted iodo-BCPs. A wide variety of radical acceptors and iodo-BCPAs are accommodated, providing straightforward access to an array of valuable aniline-like isosteres.

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Twofold Radical-Based Synthesis of N,C-Difunctionalized Bicyclo[1.1.1]pentanes

et al. 2021

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“…A [3+2] annulation sequence that used the initial opening of an aziridinylcarbinyl radical for the synthesis of pyrrolidine derivatives was described recently 51. 2‐Methyleneaziridines were introduced as functional groups for the generation of aziridinylcarbinyl radicals 52.…”

Section: Epoxide Oxetane and Aziridine Opening Through Generatiomentioning

confidence: 99%

Strained Heterocycles in Radical Chemistry

2003

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Over the last few decades the use of radicals in synthesis has witnessed an explosive growth through introduction of efficient chain and electron-transfer reactions. Strained heterocycles, in particular, have emerged as a highly versatile and readily available class of radical precursors. The generation of carbinyl radicals of heterocycles has resulted in many elegant applications of heteroatom-centered radicals, such as beta fragmentations, cyclizations, and intramolecular hydrogen atom abstractions. Direct electron transfer to strained heterocycles has been realized through the use of arene radical anions. The method combines the virtues of radical and organometallic chemistry to yield useful functionalized organolithium compounds. Epoxides have been opened with high regioselectivity by titanocene(III) reagents in either stoichiometric or catalytic quantities to yield beta-titanoxy radicals. This development has resulted in many new applications in natural product synthesis.

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“…Pyrrolidin‐Derivate wurden kürzlich in einer [3+2]‐Anellierungssequenz erhalten, die mit der Öffnung eines Aziridinylcarbinylradikals eingeleitet wird 51. Auch 2‐Methylenaziridine konnten als Edukte für eine interessante Synthese von Aziridinylcarbinylradikalen etabliert werden 52.…”

Section: Epoxid‐ Oxetan‐ Und Aziridinöffnung Durch Bildung Der Enunclassified

Gespannte Heterocyclen in der Radikalchemie

2003

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In den vergangenen Jahrzehnten ist die Zahl der Anwendungen von Radikalen in der Synthese durch die Einführung effizienter Ketten‐ und Elektronentransfer‐Reaktionen sprunghaft angestiegen. Insbesondere gespannte Heterocyclen haben sich als nützliche und leicht zugängliche Radikalvorstufen erwiesen. Die Erzeugung von Carbinylradikalen der Heterocyclen hat viele elegante Anwendungen von Heteroatom‐zentrierten Radikalen ermöglicht, z. B. β‐Fragmentierungen, Cyclisierungen und intramolekulare Wasserstoffatomabstraktionen. Mit aromatischen Radikalanionen gelingt der direkte Elektronentransfer auf gespannte Heterocyclen. Die folgende Ringöffnung vereint die Vorzüge von metallorganischer Chemie und Radikalchemie bei der Synthese funktionalisierter Organolithiumreagentien. Epoxide werden mit hoher Regioselektivität durch stöchiometrische oder katalytische Mengen an Titanocen(III)‐Reagentien zu β‐Titanoxyradikalen geöffnet. Dadurch sind zahlreiche neue Anwendungen in der Naturstoffsynthese denkbar.

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Cited by 4 publications

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Twofold Radical-Based Synthesis of N,C-Difunctionalized Bicyclo[1.1.1]pentanes

Twofold Radical-Based Synthesis of N,C-Difunctionalized Bicyclo[1.1.1]pentanes

Strained Heterocycles in Radical Chemistry

Gespannte Heterocyclen in der Radikalchemie

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