Phenyliodonium diacetate

Another synthesis, described in detail in Scheme 12, was devised specifically for the introduction of deuterium at both ends of l-deoxy-D-t/ireo-pentulose.21,22 Stannylene methodology was used twice, first for glycol splitting with phenyliodonium diacetate, under strictly neutral conditions (necessary to preserve the benzylidene acetal), and secondly to convert the sequence -CHOH-CD3 to CO-CD3 by brominolysis. The final, labeled pentulose was l-deo y-D-threo-(1-2H3, 5-2H)pentulose. 

Phenyliodonium diacetate,274 275 and phenyliodonium to-trifluoroacetate, 276 are also useful oxidants for converting amides to carbamates. 

Section B shows some Hofmann rearrangements. Entry 9, using basic conditions with bromine, provided an inexpensive route to an intermediate for a commercial synthesis of an herbicide. Entry 10, which uses the Pb(OAc)4 conditions (see p. 949), was utilized in an enantiospecific synthesis of the naturally occurring analagesic (-)-epibatidine. Entry 11 uses phenyliodonium diacetate as the reagent. The product is the result of cyclization of the intermediate isocyanate and was used in an enantioselective synthesis of the antianxiety drug (tf)-fluoxetine. 

Fragmentation of alkoxy radicals finds use in construction of medium-size rings.364 One useful reagent combination is phenyliodonium diacetate and iodine.365 The radical formed by fragmentation is normally oxidized to the corresponding carbo-cation and trapped by iodide or another nucleophile. 

The reactions can also be effected by phenyliodonium diacetate.377 A mechanistic prototype can be found in the conversion of pentanol to 2-methyltetrahydrofuran. The secondary radical is most likely captured by iodine or oxidized to the carbocation prior to cyclization.378... 

The overall transformation can also be accomplished by reaction of thallium(I) carboxylate with bromine.278 Phenyliodonium diacetate and bromine also lead to brominative decarboxylation.279... 

In addition to conventional generation of carbenes from nitrodiazo compounds (22) (79), target intermediates C can be prepared by oxidation of functionalized AN CH2XNO2 with phenyliodonium diacetate. The reactions of Rhodium intermediates with certain olefins afford the corresponding cyclopropanes (23). The cycloaddition reaction was performed in the presence of a catalyst. (The successful synthesis of nitrocyclopropanes from trinitromethane derivatives and nitroacetic ester was also documented (81)). 

Effective synthesis of spiroisoxazoline derivatives was elaborated using hypervalent iodine reagents. Thus, treatment of o-phenolic oximes 217 with phenyliodonium diacetate (PIDA) in MeCN at 0°C afforded spiroisoxazoUnes 218 in moderate yields (equation 94) . Oximes 219, prepared in situ from 2-trifluoromethylchromones, in the acidic media also led to spiroisoxazoUnes 220 (equation 95) . ... 

Phenyliodonium diacetate,182 183 184 phenyliodonium trifluoroacetate,185 and iodosobenzene diacetate186 187 are also useful oxidants for amides. 

The accessibility of position 9 becomes much higher when an activating group, such as an OH, is present in position 10. Although 10-hydroxycamptothecin (8) is available in small amounts from the plant material, two efficient preparations of this compound were developed, via catalytic reduction of CPT in acid medium to a tetrahydroquinoline, followed by selective oxidation with lead tetraacetate [8], or phenyliodonium diacetate [27], or via a photochemical rearrangement of camptothe-... 

The starting phenyliodonium ylides 3 are prepared simply from the corresponding bis(sul-fonyl)methane and phenyliodonium diacetate. ... 

The oxidation of a ( )-flavanone with Tl(ni) nitrate, Pb tetracetate, phenyliodonium diacetate (PIDA), or [hydroxyl(tosyloxy)iodo]benzene in trimethyl orthofonnate affords the corresponding ( )-2,3-dihydrobenzo[h]furan derivative as a major product. The structures, including the relative stereochemistry, and a plausible mechanism of formation are reported. The preferred formation of a flavone from the ( )-flavanone by PIDA is explained by quantum-chemical calculations on the intermediate formed by the addition of this reagent to the enol ether derivative of the ( )-flavanone." Formation of mixed anhydrides by rapid oxidation of aldehydes, activated by pivalic acid, Bu OCl in presence of pyridine and MeCN is catalysed by TEMPO (2,2,6,6-tetramethylpiperidin-l-oxyl). The anhydrides can be converted in situ to esters, secondary, tertiary or Weinreb amides in high yield. Oxidation of the aldehyde to 2-propyl esters is also possible using only catalytic amounts of pivalic acid." ... 

Oxidation of carbonyl compounds with organo-hypervalent iodine reagents has been reviewed. The hypervalent iodine oxidation of several a-substituted 2,4-dihydroxyacetophenones (12) (Scheme 6) using phenyliodonium diacetate (PIDA) proceeds via rearrangement of an iodonium ylide (13) to afford novel o-iodophenoxy ethers (14). ... 

Xu J-H, Jiang Q, Guo C-C (2013) Phenyliodonium diacetate mediated direct synthesis of benzonitriles from styrenes through oxidative cleavage of C=C bonds. J Oig Chem 78 (23) 11881-11886... 

Murakata, M., Yamada, K., and Hoshino, O. (1998) Studies on synthesis of araplysillins via oxidative cyclisation of o-phenolic oxime-add derivatives using phenyliodonium diacetate. Heterocycles, 47,921-931. 

Murakata et al. synthesized the cyclohexadienonespiroisoxazoline amides 324, which could be useful as intermediates for the synthesis of araplysillin I (99) and II (100) (223). The synthesis of these metabolites was efficiently achieved using two routes. The first route is direct cyclization of o-phenolic oxime-amide 325 with phenyliodonium diacetate (PIDA) to produce 324. The second is the amidation of the cyclohexadienonespiroisoxazohne-add 326 to afford 324. 

---