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Heavy metal reagents

A variety of methods have been described to solve the task in solution.16 Common oxidative agents for this transformation include various heavy-metal reagents such as chromium-or ruthenium-based oxides, pyri-dine-S03, and dimethylsulfoxide (DMSO) in combination with acetic anhydride, carbodiimide, or oxalyl chloride for activation. One of the most prominent methods for the reliable conversion of sensitive compounds is the Dess-Martin reagent or its nonacetylated equivalent, 1-hydroxy-(17/)-benzo-l,2-iodoxol-3-one-l-oxide (2-iodoxybenzoic acid, IBX). [Pg.371]

Iodonium salts are at present receiving much attention because of their similar reactivity to those of heavy metal reagents. The results of the application of salt are close to electrochemical oxidation. Added advantages that render them synthetically more attractive are their low toxicity, ready availability, and easy handling. In contrast to the anodic version, the iodonium reactions are amendable to large-scale synthesis. [Pg.333]

Maritidine. It was observed that a variety of alkoxyl or silyloxy phenols 340 (Scheme 51), on oxidation with the non-toxic pheny 1 iodo-tos-trifluoroacetate, instead of customary heavy metal reagents such as trivalent thallium or pentavalent vanadium salts, in the weakly nucleophilic solvent, trifluoroethanol at low temperature, furnished consistently improved yields of cyclisation products 341 [89],... [Pg.519]

Recently, in consideration of the environment, heavy metal oxidants such as lead(IV),thallium(III), and mercury(II) cannot be used for industrial processes, especially for pharmaceutical and agrochemical processes, due to their high toxicity and serious amount of metal waste. Hypervalent iodine reagents are now extensively used in organic synthesis as a mild, safe, and economical alternative for heavy metal reagents (Fig. 1). [Pg.210]

In particular, (diacyloxyiodo)benzene such as phenyliodine(III) diacetate (PIDA) and phenyliodine(III) bis(trifluoroacetate) (PIFA) have received a great deal of attention due to their reactivities similar to those of heavy metal reagents or anodic oxidation, low toxicity, ready availability and easy handling. Accordingly, a variety of useful oxidation reactions using iodine(III) or iodine(V) reagents have been developed recently. A number of previous review articles and... [Pg.210]

Heavy-metal reagent accumulates in the gap between collagen molecules... [Pg.124]

Hypervalent iodine reagents have recently received a great deal of attention in organic synthesis, not only as a mild, safe, and economical alternative to heavy metal reagents, but also because of their variety of unique reactivities applicable to natural product syntheses. Pioneering studies on hypervalent iodine-induced reactions toward total syntheses of several natural products were reported by Kishi and co-workers in the 1970s [34]. Based on the hypervalent iodine-induced oxidative cyclization, a formal stereospecific synthesis of sporidesmin A, a toxic metabolite of Pithomyces chartarum, was accomplished, albeit in low yield from the key reaction of the tryptamine derivative at the indole ring (Scheme 5). [Pg.6]

The use of heavy metal reagents in the olefination of carbonyl compounds is in its infancy. However. Kauffmann and co-workers have shown that the phenyl-thio(triphenyl-stannyl or -plumbyl)methyl-lithiums (170) react with benz-aldehyde to give mixtures of threo- (171) and erythro- adducts (173). After the isomers are separated, each is capable of being converted into the ( )- or (Z)-p-phenylthiostyrene, (172) or (174), respectively, stereospecifically, as shown in Scheme 23. [Pg.27]


See other pages where Heavy metal reagents is mentioned: [Pg.7]    [Pg.368]    [Pg.268]    [Pg.3]    [Pg.209]    [Pg.279]    [Pg.123]    [Pg.323]    [Pg.186]    [Pg.307]    [Pg.30]    [Pg.125]    [Pg.51]    [Pg.418]    [Pg.553]    [Pg.71]    [Pg.25]    [Pg.128]    [Pg.136]    [Pg.88]    [Pg.201]    [Pg.213]    [Pg.239]   
See also in sourсe #XX -- [ Pg.209 , Pg.210 ]




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Metals reagents

Organic reagents, heavy metal removal from

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