Facile Preparation and Reactivity of Polymer-Supported <i>N</i>-(2-Iodyl-phenyl)-acylamide, an Efficient Oxidizing System

Ladziata, Vladimir; Willging, Jeff; Zhdankin, Viktor V.

doi:10.1021/ol052684r

Cited by 52 publications

(28 citation statements)

References 21 publications

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“…Based on the remarkable acceleration of the oxidation of phenols by addition of only a small amount of iodoarene and documented examples of the reactions of iodoarene and Oxone ® , which produce pentavalent iodine species, [43][44][45][46][47][48] it was suggested that iodine(V) species, generated in situ, was included in this oxidation as the active catalyst. However, formation of pentavalent iodine species requires a higher temperature (70°C) than that in the oxidation of 2 with 1a and Oxone ® .…”

Section: Resultsmentioning

confidence: 99%

Catalytic Hypervalent Iodine Oxidation Using 4-Iodophenoxyacetic Acid and Oxone: Oxidation of p-Alkoxyphenols to p-Benzoquinones

Yakura

Tian

Yamauchi

et al. 2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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Hypervalent iodine compounds, trivalent iodine compounds such as phenyliodine(III) diacetate (PIDA) and phenyliodine(III) trifluoroacetate (PIFA) and pentavalent iodine reagents such as Dess-Martin periodinane (DMP) and o-iodoxybenzoic acid (IBX), have been used extensively in recent organic synthesis because of their low toxicity, ready availability and easy handling. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, these reagents are highly expensive. And stoichiometric amounts of iodine reagents are required to produce equimolar amounts of organic iodine waste. Moreover, pentavalent iodine reagents are potentially explosive. To overcome these disadvantages, catalytic hypervalent iodine oxidations [16][17][18] using mchloroperbenzoic acid (m-CPBA), [19][20][21][22][23][24][25][26][27] Oxone ® (2KHSO 5 · KHSO 4 · K 2 SO 4 ), 28,29) and H 2 O 2 30) as a co-oxidant have been reported recently.Development of efficient methods for synthesis of pquinone and p-quinone derivatives is an important subject in synthetic organic chemistry because they are structural components of numerous natural products and useful synthetic intermediates. [31][32][33][34][35][36] A convenient procedure for p-quinones was hypervalent iodine oxidation of p-alkoxyphenols using PIFA.37) Reactions of p-alkoxyphenols with an equimolar amount of PIFA in a 2 : 1 mixture of acetonitrile and water at room temperature gave the corresponding p-quinones in excellent yield.As part of our study for development of practical and environmentally benign oxidation, we report a mild, efficient and practical procedure for catalytic hypervalent iodine oxidation of p-alkoxyphenols to p-quinones using a catalytic amount of 4-iodophenoxyacetic acid (1a) and Oxone ® as a co-oxidant 38) in 2,2,2-trifluoroethanol-water. Results and DiscussionWe chose Oxone ® as an environmentally safe co-oxidant for a catalytic hypervalent iodine oxidation of p-alkoxyphenols because Oxone ® is an inorganic and water-soluble oxidant with a low order of toxicity, moreover, it is commercially available and inexpensive. 39) Oxone ® has been already used as a co-oxidant under heating conditions in the catalytic IBX oxidation by Vinod 28) and Giannis 29) groups, independently. Because alkoxyphenols have high reactivity under oxidation conditions, we first investigated the oxidative ability of Oxone ® itself. 40) A mixture of 2-pivaloyloxymethyl-4-methoxyphenol (2a) and an equimolar amount of Oxone ® in acetonitrile-water (2 : 1) at room temperature gave the corresponding p-benzoquinone (3a), but the reaction was sluggish and the yield of 3a was only 13% along with 78% of recovered starting 2a after 24 h. Next, we examined reactions of 2a in the presence of several iodoarenes as a catalyst (Chart 1). Table 1 presents the results. According to the procedure reported by Vinod, 28) a mixture of 2a, 0.2 equivalents (eq) of 2-iodobenzoic acid, and 1 eq of Oxone ® in acetonitrile-water was heated at 70°C for 19 h to give a complicated mixture (entry 2). However, a similar reactio...

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Section: Resultsmentioning

confidence: 99%

Catalytic Hypervalent Iodine Oxidation Using 4-Iodophenoxyacetic Acid and Oxone: Oxidation of p-Alkoxyphenols to p-Benzoquinones

Yakura

Tian

Yamauchi

et al. 2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…For biologically active compounds containing the acylamide system, see: Bennasar et al (2006); Ladziata et al (2006). For bond-length data, see: Gao et al (2007).…”

Section: Related Literaturementioning

confidence: 99%

2-(Benzo[d]thiazol-2-ylsulfanyl)-N-(6-methyl-2-pyridyl)acetamide

Zhao

Wang

et al. 2009

Acta Cryst E

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In the title compound, C15H13N3OS2, the pyridine ring and the benzo[d]thiazole unit subtend a dihedral angle of 57.7 (2)°. The length of the Csp 2—S bond [1.7462 (17) Å] is significantly shorter than that of the Csp 3—S bond [1.8133 (18) Å]. The crystal structure is stabilized by intramolecular N—H⋯N and intermolecular C—H⋯O and C—H⋯N hydrogen-bond interactions. Furthermore, C—H⋯π interactions stabilize the crystal packing.

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“…To avoid the supplementary preparation of tetrabutylammonium oxone, we have examined the oxidation of the polymer 41 in a dichloromethane/water biphasic system using oxone, tetrabutylammonium hydrogen sulfate and methanesulfonic acid. 20 The synthesis employs commercially available aminomethylated polystyrene, includes three simple steps, and affords the resin with good loading (0.70-0.80 mmol·g -1 ). These loading levels are comparable with the values reported for IBX amide resin (0.65-0.98 mmol·g -1 ).…”

Section: Polymer-supported N-(2-iodylphenyl)acylamide (Nipa Resin)mentioning

confidence: 99%

“…20 Most alcohols were oxidized to the respective aldehyde or ketone products in excellent purities and yields. As one exception, oxidation of 3-(pyridin-2-yl)propan-1-ol (Table 2, entry 20) led to the formation of a black tar, presumably due to the instability of pyridinylpropanal towards heating.…”

Section: Polymer-supported N-(2-iodylphenyl)acylamide (Nipa Resin)mentioning

confidence: 99%

N-(2-Iodylphenyl)acylamides - New Pentavalent Iodine Oxidizing Reagents

Ladziata¹,

Zhdankin²

2007

Synlett

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This account describes design and synthetic utilization of new iodine(V) oxidizing reagents, N-(2-iodylphenyl)acylamides (NIPAs). NIPA reagents are soluble and stable pseudo-cyclic IBX analogues that are able to selectively oxidize either alcohols or sulfides, with the reactivity depending largely on the substitution pattern on the amido group adjacent to the iodyl moiety. A recyclable polymer-supported version of NIPA (NIPA resin) can conveniently be prepared in three simple steps. NIPA resin can effect smooth and efficient oxidation of a large variety of alcohols to the respective carbonyl compounds. Proline-based NIPA derivatives are promising chiral oxidants based on a pseudo-benziodoxazine scaffold.

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Facile Preparation and Reactivity of Polymer-Supported N-(2-Iodyl-phenyl)-acylamide, an Efficient Oxidizing System

Cited by 52 publications

References 21 publications

Catalytic Hypervalent Iodine Oxidation Using 4-Iodophenoxyacetic Acid and Oxone: Oxidation of p-Alkoxyphenols to p-Benzoquinones

Catalytic Hypervalent Iodine Oxidation Using 4-Iodophenoxyacetic Acid and Oxone: Oxidation of p-Alkoxyphenols to p-Benzoquinones

2-(Benzo[d]thiazol-2-ylsulfanyl)-N-(6-methyl-2-pyridyl)acetamide

N-(2-Iodylphenyl)acylamides - New Pentavalent Iodine Oxidizing Reagents

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