Oxidation of olefins by potassium permanganate. Mechanism of .alpha.-ketol formation

Wolfe, Saul; Ingold, Christopher F.; Lemieux, R. U.

doi:10.1021/ja00394a037

Cited by 59 publications

(39 citation statements)

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“…This suggestion is consistent with the observation made by Carrington and Symons (17) that manganate(V) is stable only under very basic conditions; in more acidic solutions reduction to manganese dioxide is rapid and autocatalytic (15).…”

Section: Discussionsupporting

confidence: 93%

Oxidation of hydrocarbons. 13. The oxidation of cinnamate ion by alkaline permanganate

Lee¹,

Nagarajan²

1985

Can. J. Chem.

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The rates of oxidation of cinnamate ion by permanganate have been compared under conditions where distinctly different products [Formula: see text] are obtained. Since the rates of both reactions respond in similar ways to substituent effects, deuterium substitution on the double bond, and to temperature changes, it may be concluded that the different products are due to post transition state reactions. Reaction sequences that are consistent with this conclusion and with the observed stoichiometries have been suggested.

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Section: Discussionsupporting

confidence: 93%

Oxidation of hydrocarbons. 13. The oxidation of cinnamate ion by alkaline permanganate

Lee¹,

Nagarajan²

1985

Can. J. Chem.

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“…Treatment of 6 with Ac 2 O/pyridine (1:2, v/v) gave a monoacetate derivative, indicating one of the two alcohol groups to be tertiary. The presence of the mono-THF ring was established by EIMS fragment ions at m/z (%) ϭ 201 (60) [M ϩ Ϫ AcOCH 2-CHOH] and 187 (25) [M ϩ Ϫ AcOCH 2 C(CH 3 )OH]. The 1 H NMR spectrum of 6 showed the presence of a pure AB system centred at δ ϭ 4.08 (J ϭ 11.0 Hz) attributable to the 5-C(CH 3 )(OH)CH 2 OAc protons.…”

Section: Resultsmentioning

confidence: 99%

Reactions of 1,5-Dienes with Ruthenium Tetraoxide: Stereoselective Synthesis of Tetrahydrofurandiols

2001

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An improved procedure for the ruthenium tetraoxide catalysed oxidation of 1,5-dienes, employing 0.05 equiv. of the catalyst RuO 2 ·2H 2 O, 2.5 equiv. of NaIO 4 as a stoichiometric oxidant, and a biphasic solvent system of AcOEt/(CH 3 ) 2 CO/ H 2 O (2:1:1, v/v/v), is presented. Reactions of 1,5-dienes 1, 3, and 5 furnished the new cis-tetrahydrofuran products 2, 4, 6, and 7 with total stereospecificity. The structures of the products have been established on the basis of NMR and MS data, as well as chemical evidence. Application of this procedure to geranyl acetate (8) and neryl acetate (12) afforded the cis-tetrahydrofuran derivatives 9, 10, and 13 in high yields, accompanied by small amounts of trans-tetrahydrofu-

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“…Finally, relief of the bond-angle strain when the nanotube opens to the graphene ribbon (5, Fig. 1b) slows further dione formation and cutting 20 . Thus, the preference for sequential bond cleavage over random opening and subsequent cutting, as occurs with nitric acid oxidation, can be explained by concerted attachment to neighbouring carbon atoms by permanganate, contrasting with the random attack on nonneighbouring carbon atoms by the nitronium species from nitric acid.…”

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confidence: 99%

Longitudinal unzipping of carbon nanotubes to form graphene nanoribbons

Kosynkin¹,

Higginbotham²,

Sinitskii³

et al. 2009

Nature

3,369

2,759

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Graphene, or single-layered graphite, with its high crystallinity and interesting semimetal electronic properties, has emerged as an exciting two-dimensional material showing great promise for the fabrication of nanoscale devices [1][2][3] . Thin, elongated strips of graphene that possess straight edges, termed graphene ribbons, gradually transform from semiconductors to semimetals as their width increases 4-7 , and represent a particularly versatile variety of graphene. Several lithographic 7,8 , chemical 9-11 and synthetic 12 procedures are known to produce microscopic samples of graphene nanoribbons, and one chemical vapour deposition process 13 has successfully produced macroscopic quantities of nanoribbons at 950 6C. Here we describe a simple solution-based oxidative process for producing a nearly 100% yield of nanoribbon structures by lengthwise cutting and unravelling of multiwalled carbon nanotube (MWCNT) side walls. Although oxidative shortening of MWCNTs has previously been achieved 14 , lengthwise cutting is hitherto unreported. Ribbon structures with high water solubility are obtained. Subsequent chemical reduction of the nanoribbons from MWCNTs results in restoration of electrical conductivity. These early results affording nanoribbons could eventually lead to applications in fields of electronics and composite materials where bulk quantities of nanoribbons are required [15][16][17] .We obtained oxidized nanoribbons by suspending MWCNTs in concentrated sulphuric acid followed by treatment with 500 wt% KMnO 4 for 1 h at room temperature (22 uC) and 1 h at 55-70 uC (Methods). After isolation, the resulting nanoribbons were highly soluble in water (12 mg ml 21 ), ethanol and other polar organic solvents. The opening of the nanotubes appears to occur along a line, similar to the 'unzipping' of graphite oxide 18,19 , affording straightedged ribbons. This could occur in a linear longitudinal cut (Fig. 1a) or in a spiralling manner, depending upon the initial site of attack and the chiral angle of the nanotube. Although depicted in Fig. 1a as occurring on the mid-section of the nanotube rather than at one end, the location of the initial attack is not known.The mechanism of opening is based on previous work on the oxidation of alkenes by permanganate in acid. The proposed first step in the process is manganate ester formation (2, Fig. 1b) as the ratedetermining step, and further oxidation is possible to afford the dione (3, Fig. 1b) in the dehydrating medium 20 . Juxtaposition of the buttressing ketones distorts the b,c-alkenes (red in 3), making them more prone to the next attack by permanganate. As the process continues, the buttressing-induced strain on the b,c-alkenes lessens because there is more space for carbonyl projection; however, the bond-angle strain induced by the enlarging hole (or tear if originating from the end of the nanotube) would make the b,c-alkenes (4, Fig. 1b) increasingly reactive. Hence, once an opening has been initiated, its further opening is enhanced relative to an unopened ...

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Oxidation of olefins by potassium permanganate. Mechanism of .alpha.-ketol formation

Cited by 59 publications

References 0 publications

Oxidation of hydrocarbons. 13. The oxidation of cinnamate ion by alkaline permanganate

Oxidation of hydrocarbons. 13. The oxidation of cinnamate ion by alkaline permanganate

Reactions of 1,5-Dienes with Ruthenium Tetraoxide: Stereoselective Synthesis of Tetrahydrofurandiols

Longitudinal unzipping of carbon nanotubes to form graphene nanoribbons

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