Reductions iodide

Oxaziridines are powerful oxidizing agents. Free halogen is formed from hydrobromic acid (B-67MI50800). Reduction by iodide in acidic media generally yields a carbonyl compound, an amine and two equivalents of iodine from an oxaziridine (1). With 2-alkyl-, 2-acyl and with N-unsubstituted oxaziridines the reaction proceeds practically quantitatively and has been used in characterization. Owing to fast competing reactions, iodide reduction of 2-aryloxaziridines does not proceed quantitatively but may serve as a hint to their presence. 

Fluorodiazirines are obtained from suitable perfluoro compounds by reduction. Difluorodiazirine (218) was prepared from perfluoromethylenediamine (290) by reduction with ferrocene (66JHC245), or from perfluoroformamidine (291) by iodide reduction (67JOC1944). 

A study of nonsteroidal examples has led to the suggestion that the elimination of vicinal ditosylates involves nucleophilic displacement of one tosy-late by iodide. Reductive elimination then occurs if the geometry is correct otherwise, a second displacement occurs which then gives the required trans arrangement. The reason for the failure of reaction with 2jS (axial) isomers is not clear. 

The amines which are formed by the iodide reduction [Eq. (41)] can be isolated and used in the proof of structure of the diaziridines. For example, ammonia and cyclohexylamine were obtained from 1-cyclohexyldiaziridine [Eq. (42)] cyclohexylamine and phenylurea were obtained from the acylated diaziridine 58 [Eq. (43)]. ... 

Samarium(n) iodide reduction of benzothiazinium salt 87d at room temperature gave exclusively formation of the medium-sized lactam sulfide 89d, as shown in Equation (23) <1997J(P1)309>. 

REDUCTION WITH ZINC AND SODIUM IODIDE Reductive Cleavage of Sulfonates to Hydrocarbons [700]... 

Hydrogen iodide reduction has recently been used1 also in the steroid field to effect reduction of the 6/V7j -epoxide derivative ehn -n in Eq. (411). 

C") Chlorite-iodine-reductant. These systems, which include systems 8 b, 9 b and 10b of Table 8 appear to be only minor variants of type C ) in which (M 9) replaces (M 8). C ") Chlorite-iodide-reductant. The only known example of this type is the chlorite-iodide-malonic acid system, which is of special interest because it supports both batch oscillations and spatial wave patterns. The slow decomposition of iodinated malonic acid species apparently provides a long lasting, indirect flux of iodide (via (M2) + (M9)) in this system. 

Although Curran s rate data for the reduction of radicals to organosamar-iums allow for an element of predictablity,2 problems can arise when multifunctional substrates are involved. For example, in the attempted intramolecular Barbier reaction of alkyl iodide 13, treatment with Sml2 results in the formation of side product 15 in addition to the expected product cyclohexanol 14 (Scheme 3.7).8 In this case, the p-keto amide motif in 13 is reduced at a rate competitive with alkyl iodide reduction, indicating that there are likely two mechanistic pathways through which the reaction proceeds a thermodynamic pathway initiated by reduction of the R I bond providing the... 

This is, as expected, the rarest oxidation state as far as non-organometallic complexes of rhenium are concerned. The dirhenium phosphite complex Re2[P(OMe)3]10 has been prepared12,13 in low yield by several methods, viz. the potassium-potassium iodide reduction of ReOCl3(py)2 or an ReCLj-pyridine complex, followed by treatment with trimethyl phosphite. This yellow complex displays a 31P H) NMR spectrum that appears as a first order AB4 pattern, and is isoelectronic with Re2(CO)l0. It reacts with H2 upon photolysis in THF solution to produce hydridorhenium(III) and other species.13 The related triphenyl phosphite derivative Re2[P(OPh)3]l0 has been described14 as a product of the reaction between ReH3(PPh3)4 and P(OPh)3. 

The reduction of the /r-amido //-peroxo complex with arsenite also gives a //-NH2 fi-OH species and may follow a mechanism similar to the iodide reduction . A detailed study by Sykes of the Cr " reduction of [(en)2Co(M-NH2)(M-02)Co(en)2] has shown the initial step to involve inner sphere attack of Cr " on the peroxo bridge followed by loss of Co to give a Co(III)-02 -Cr(III) complex. The succeeding steps involve protonation, isomerisation and reduction of the peroxo bridge, and only in the last step is the second Co(III) group reduced. 

The reaction of iodide with [(en)2Co( r-OH)( -02)Co(en)2] in acid solution gives [Co(en)2(OH2)2] and iodine. The rate has been shown to be the same as that of dissociation in acid solution (reaction 12) and the initial step is hydrolysis of the /i-hydroxo group followed by I" attack on the monobridged species. The monobridged complex [(H3N)5Co(02)Co(NH3)5] produced by iodide reduction of the superoxo complex does not react with iodide but decomposes to Co(II) and ammonia The reduction of the mononuclear -peroxo complex [(H3N)5Co(02)Co(NH3)s] by or... 

Hydrogen iodide reduction hes recently been uBed " eleo in the eterdd field to effect reductioD of the J ,7i -epoxide derivetlve ehn .-n inEq.(4U). 

Williams carried out a Julia coupling similar to the Keck example. With the removal of the acetal functionality, the coupling step of the Julia reaction was efficient, but the usual reductive elimination procedure failed. As an alternative to the acetylation and reductive elimination procedure, the P-sulfo-nyl xanthate was formed by quenching the addition reaction with carbon disulfide and methyl iodide. Reductive elimination was then carried out with tri-n-butyltin hydride to yield the desired ( )-alkene (399) in an 85 15 ratio with the (Z)-alkene in 83% overall yield (equation 91). 

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