In situ generated tris(p-bromophenyl)amine radical cation promoted electron transfer reaction of cyclopropyl silyl ethers

Hasegawa, Eietsu; Kakinuma, Koji; Yanaki, Tomoyo; Komata, Shota

doi:10.1016/j.tet.2009.09.108

Cited by 9 publications

(5 citation statements)

References 67 publications

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“…Other reagents and solvents were purchased and used without further purification. Substrates 1a [25], 1b [29], 1d [29], 6b [24], and 6d [28] and products 2 [24], 3 [25], 4 [25], 5 [29], 19 [25], 20 [26], 25 [25], and 26 [25] are known compounds. Spectral data of 1c , 6c , 14 , 15 , 16 , 21 , 22 , and 23 are presented below.…”

Section: Methodsmentioning

confidence: 99%

Copper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives via radical pathways

Hasegawa

Tateyama²,

Nagumo³

et al. 2013

Beilstein J. Org. Chem.

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SummaryCopper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives were investigated. The regioselectivities of these processes were found to be influenced by the structure of cyclopropanols as well as the counter anion of the copper(II) salts. A mechanism involving rearrangement reactions of radical intermediates and their competitive trapping by copper ions is proposed.

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Section: Methodsmentioning

confidence: 99%

Copper(II)-salt-promoted oxidative ring-opening reactions of bicyclic cyclopropanol derivatives via radical pathways

Hasegawa

Tateyama²,

Nagumo³

et al. 2013

Beilstein J. Org. Chem.

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“…A recent example of the homo-Reformatsky reaction was disclosed by Evans and co-workers in 2008, in a report on the total synthesis of (+)-azaspiracid-1 (172) (Scheme 42). 104 Here, the authors used diisobutylaluminium hydride (DIBAL) to convert the desired ester (170) to the aldehyde. Then, silyl cyclopropanone hemiacetal 169 was used to perform a homo-Reformatsky reaction in the presence of ZnCl 2 to deliver the homoaldol adduct (171) Zercher and co-workers have found that their β-ketoester chain-extension reaction can be terminated with an aldol reaction to generate homoaldol adducts (174) (Scheme 43).…”

Section: β-Functionalization With Heteroatom−x Electrophilesmentioning

confidence: 99%

“…169 In 2009, Hasegawa demonstrated that tris(p-bromophenyl)amine radical cations are effective oxidizing agents in the ring opening of TMS-protected cyclopropyl alcohols. 170 Similar to the metal oxidants that are frequently seen with single electron oxidations of cyclopropyl alcohols and their derivatives, these amine radicals can also lead to endocyclic bond cleavage to yield β-keto radicals. In this report, the authors generate the amine radical cations in situ by treating the starting amine to either SbCl 5 or AgClO 4 /I 2 .…”

Section: C−c Bond Cleavage To Generate β-Ketomentioning

confidence: 99%

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

et al. 2020

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The carbon–carbon (C–C) bond cleavage of cyclopropanols is a wide area of research with much current activity. This review highlights new developments in this area over the past two decades. A summary is made of the three main reactivity modes, namely, homoenolate chemistry, β-keto radical chemistry, and acid-catalyzed ring-opening, as well as all other methods for the C–C bond cleavage and functionalization of cyclopropanols, including base-mediated ring-opening, metal-catalyzed C–C insertions and eliminations, oxidative fragmentation using hypervalent iodine reagents, reactions of donor–acceptor cyclopropanols, and pericylic reactions. Emphasis is placed on the synthetic utility of cyclopropanols and related derivatives, which have emerged as unique three-carbon synthons.

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“…Hasegawa et al carried out TTMSS-mediated radical reaction of organic halides using BTF as a solvent [8]. BTF exhibited an efficiency similar to dichloromethane in a ring-expansion reaction of a siloxycyclopropane 11 by tris(p-bromophenyl) aminium hexachloroantimonate (TBPA) (Scheme 1) [9]. Hasegawa and his coworkers also developed a binary solvent system comprised of BTF and ionic liquids for a similar oxidative ring-opening reaction of siloxycyclopropanes by FeCl 3 [10].…”

Section: Benzotrifluoridementioning

confidence: 99%