Periodinane, sodium, oxidation

The pure dry acid explodes at 233°C, and violently if confined, possibly <200°C. It is also impact-sensitive, exploding under a hammer blow, or under impact of a 534 g steel ball falling from a height of 1 m. Several of its salts (ammonium, potassium, sodium, silver, barium, calcium and magnesium) are also explosive. The acid is precursor to the Dess-Martin periodinane mild oxidant, and is produced when the latter is treated with water. 

In this work-up, the periodinane species 38s, resulting from the reduction of Dess-Martin periodinane, is further reduced with sodium thiosulfate to o-iodobenzoic acidh that is removed with a sodium bicarbonate aqueous solution. The treatment with sodium thiosulfate is normally made in the presence of sodium bicarbonate as buffer. This is the most common work-up because it is done under almost neutral conditions and the organic periodinane 38 is destroyed thus, avoiding a possible difficult chromatographic separation from the product. The o-iodobenzoic acid can be recycled back to Dess-Martin periodinane by oxidation. 

Nicolaou and coworkers have reported an expeditious IBX (2-iodo3gr-benzoic acid, l-hydro q -l, 2-benziodoxol-3(l//)-one 1-oxide) mediated synthesis of Z-vancosamine " starting from vinyl iodide and protected aldehyde via an intramolecular Kishi-Nozaki coupling reaction. The coupling product, as a mixture of alcohols, was immediately oxidized with DMP (Dess-Martin periodinane). The oxidation was followed by a sodium borohydride/cerium chloride reduction to produce a protected alcohol intermediate. In the next step, the required alcohol was reacted... 

Acyl nitroso compounds (3, Scheme 7.2) contain a nitroso group (-N=0) directly attached to a carbonyl carbon. Oxidation of an N-acyl hydroxylamine derivative provides the most direct method for the preparation of acyl C-nitroso compounds [10]. Treatment of hydroxamic acids, N-hydroxy carbamates or N-hydroxyureas with sodium periodate or tetra-alkyl ammonium periodate salts results in the formation of the corresponding acyl nitroso species (Scheme 7.2) [11-14]. Other oxidants including the Dess-Martin periodinane and both ruthenium (II) and iridium (I) based species efficiently convert N-acyl hydroxylamines to the corresponding acyl nitroso compounds [15-18]. The Swern oxidation also provides a useful alternative procedure for the oxidative preparation of acyl nitroso species [19]. Horseradish peroxidase (HRP) catalyzed oxidation of N-hydroxyurea with hydrogen peroxide forms an acyl nitroso species, which can be trapped with 1, 3-cyclohexanone, giving evidence of the formation of these species with enzymatic oxidants [20]. 

It is possible to perform an oxidation with Dess-Martin periodinane under almost neutral conditions by adding pyridine to the reaction flask in order to neutralize the acetic acid, which is generated during the oxidation, and performing the work-up by treatment with sodium thiosulfate in the presence of a sodium bicarbonate buffer.2... 

Reaction of the benzodioxocine 170 with the epoxidation reagent resulted in the epoxide 171, which was then opened with sodium azide in situ to provide trans-racemic azide 172 (Scheme 18) <2004MI265>. Reduction of the azide 172 by hydrogenolysis using Pd on carbon gave trans-racemic amine 173 in 70% yield over three steps. On acylation of the amine with acetic anhydride, the trans-racemic alcohol 174 was formed, which was then oxidized with Dess-Martin periodinane into the unstable dioxocinone 175. 

The following Swern oxidation is an inexpensive, mild and fast transformation. It provides aldehydes starting from primary alcohols in the absence of water, exclusively. Other mild oxidation methods for the formation of aldehydes are known Dess-Martin periodinane (DMP), o-iodoxybenzoic acid (IBX), chromium(III) reagents, tetramethylpiperidine 7V-oxide and sodium hypochlorite (TEMPO/NaOCl), tetrapropylammonium perruthenate and N-methylmorpholine 7V-oxide (TPAP/NMO), " and palladium(II)-catalyzed oxidations are reported. ... 

IBX in the solid state has a three-dimensional polymeric stmcture due to strong intermolecular secondary I - O contacts and hydrogen bonding. A detailed X-ray diffraction study of IBX samples, prepared by the oxidation of 2-iodobenzoic acid with potassium bromate, revealed the presence of the powder and the macrocrystalline forms of IBX [674]. It was also noticed that the powder form of IBX is more reactive in the reaction with acetic anhydride than the macrocrystalline form and thus is more useful as the Dess-Martin periodinane precursor (Section 2.23.2). Treatment of macrocrystalline IBX with aqueous sodium hydroxide and then with hydrochloric acid can be used to convert it into the more reactive powder form [674]. 

The second starting material, mesylate 426, was synthesized from alcohol 422. Swern oxidation followed by addition of propargyl zinc bromide led to compound 423 in 79% yield, which was converted into thionocarbonate 424 (41% yield over three steps). Radical ring closure with tributyltin hydride and oxidation with Dess-Martin periodinane afforded ketone 425. Treatment with DMAP led to the rearrangement of the double bond and subsequent reduction with sodium borohydride and mesylation gave compotmd 426 (Scheme 8.6). 

As an example of the use of this methodology in total synthesis, the zirconocene-promoted ring contraction was the key step in the route to (+)-epiafricanol (100) reported by Paquette et al. [78]. Vinyl pyranose 95, obtained from D-glucose in 12 steps, was treated with Cp2Zr in toluene at -78°C and then with boron trifluoride etherate at room temperature, affording vinyl cyclopentane 96 in a 63% yield. Conversion of 96 to ketone 97 with periodinane as the oxidant in the presence of sodium bicarbonate and addition of the lithium derivative to 4,4-dimethyl-5-iodo-l-pentene 98 gave rise to 99. Cyclization of 99 by RCM followed by cyclopropanation finally afforded the desired product 100 (Scheme 3.39). 

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