4-iodobenzoic ester

Similarly, OS supported iodide can be used with the same success. For example, using only 100 ppm of Pd(OAc)2 as catalyst, it has been possible to perform the Heck reaction between a supported 4-iodobenzoic ester and /ert-butylacrylate. All parameters were evaluated in this reaction, and the overall message is that every parameter has a noticeable influence on the outcome of the reaction, including spacer length, nature of the counter anion, nature of the IL matrix, and nature of the base [18, 20], In all cases, disubstituted olefins could be isolated by transesterification of the benzoate support under basic (NH3/MeOH) or acidic (HCl/MeOH) conditions. 

Chan et al. illustrated the use of imidazohum tetrafluoborates functionalized with 3- and 4-iodobenzoic esters in SuzuH-Miyaura cross-coupling reactions [57]. These esters were prepared by esterification of l-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroboratetetrafluoborate in a mixture of acetonitrile and didiloromethane... 

A facUe synthesis of 3,4-disubstituted isocoumarins and their benzologues is based on the Pd-catalysed annulation of internal alkynes by 2-iodobenzoate esters (Scheme 27). Tri- and tetra- substituted pyran-2-ones are also available by this route <99JOC8770>. 3-Substituted isocoumarins result from the Pd-catalysed 6-endo-dig cyclisation of 2-ethynylbenzoic acids. The 5-exo-dig products, phthalides, are also formed when there is a terminal bulky group on the alkyne moiety <99S1145>. 

Imine derivatives to protect amines, 368-371 to protect carbonyl groups, 217 Indoles, to protect, 385-397 2-Iodobenzoate esters, to protect alcohols, 111... 

Chiral phthalides are synthesized from an o-iodobenzoic ester that forms a zinc compound. With a P-chiral diphosphinocobalt complex 50 present the addition to aldehydes follows an asymmetric course. ... 

We irradiated a solution of phenyliodine dichloride with the w-iodobenzoate ester 12 of 3a-cholestanol and found that C-9 chlorination occurred selectively, while no such selectivity was seen without the iodine atom on the benzoate ester [37]. Various controls established that we were not simply converting the attached iodoaryl template to its... 

Esters of 2-iodoxybenzoic acid (IBX-esters) 489 have been prepared by the hypochlorite oxidation of the readily available 2-iodobenzoate esters 488 (Scheme 2.139) and isolated in the form of stable microcrystalline solids [657,658], This procedure has been used for the synthesis of IBX-esters 489 derived from various types of alcohols, such as primary, secondary and tertiary alcohols, adamantanols, optically active menthols and borneol. Single-crystal X-ray data on products 489 revealed a pseudo-benziodoxole stmcture in which the intramolecular L--0 secondary bonds partially replace the intermolecular I - O secondary bonds, disrupting the polymeric structure characteristic of Phl02 and other previously reported iodylarenes [658], This stmctural feature substantially increases the solubility of these compounds in comparison to other iodine(V) reagents and affects their oxidizing reactivity. 

Figure 6.33 The biomimetic chlorination of steroids. The dichloride of 3a- (4-iodophenylacetyl)-cholestanol (1) activates the C-14 of the steroid nucleus, while the dichloride of the shorter 3-iodobenzoate ester (2) activates C-9. A chloride radical is delivered to these carbon atoms from a second molecule of the respective iodochlorides, and for this reason the chlorine atom derived from (1) lies above the plane of the steroid nucleus, while that derived from (2) lies below it. After Breslow, R. (1980) Acc. Chem. Res. 13, 170...

Efficient new methods for oxidation are always welcome. The Dess-Martin periodinane has become the workhorse for alcohol to aldehyde or ketone conversion in organic research labs around the world. Viktor V. Zhdankin of the University of Minnesota, Duluth has described (Chem. Commun. 2004, 106) a complementary family of reagents. Oxidation of an ester I of o-iodobenzoic acid with NaOCl delivers 2. Depending on the ester, the reagent 2 is soluble and an effective oxidant, with KBr catalysis, in a wide range of organic solvents. Presumably, the spent oxidant can be recovered and recycled. 

Chlorination of steroids (4, 264-265 5, 352-353 6, 298-299). Breslow s method for chlorination of steroids at CV has been developed into a useful method for conversion of 17a-hydroxyprogesterone (1) into the triene (4), a useful intermediate to highly active corticoids.2 The hindered I7a-hydroxyl group is esterified with m-iodobenzoic anhydride and 4-dimethylaminopyridine. Irradiation of the ester (2) with C6H5IC12 in the presence of NaOAc (HC1 scavenger) affords 3 in quantitative... 

These two reactions are limited by the fact that a nitro group must be present on the benzene ring to facilitate the elimination of the chlorine atom. However, this restriction may be removed by the use of a transition-metal complex—most often, a nickel(O) catalyst. The starting compounds are 2-iodobenzoic acid derivatives 91 (amides, nitriles, and esters) and MA-disubstituted thioureas. In this case, electron-acceptor groups in the benzene ring are not obligatory the reaction is general and allows one... 

Two novel variations on remote oxidation involve radical relay mechanisms. Chlorine radicals generated by photolysis of iodobenzene dichloride are carried by the iodine atom of a suitable iodo-aryl ester of 5a-cholestan-3a-ol to permit hydrogen abstractions from C-9 or C-14, depending upon the ester employed.237 The m-iodobenzoate (293) afforded the 9a-chloro- and thence the cholest-9(ll)-ene derivative (294), whereas the p-iodophenylacetate similarly gave a 14-ene. 

The selectivity of the radical relay chlorination is striking. In the case of the enone (13 Sdieme 18), and in related compounds with A-ring dienones, the m-iodobenzoate template at C-17 directs chlorination to C-9 and not to die preexisting functional groups of (13). The selective chlorination of C-9 seems to be quantitative, although in the first report the A "Lalkene (14) was isolated in only 77% yield. Later work has shown that the overall introduction of this double bond can have yields in the 90-93% range, and good yields for this reaction have also been reported from another laboratory. Template-directed radical relay chlorination on the a-face of steroids has also been successful in the a/b cu-coprostanol steroid series,and in the cholestanol series with iodophenyl templates linked by amide, ether, or sulfonate functions rather than carboxylic esters. ... 

Bipyridine formation has been further explored in a series of reactions between stannylated pyridine and bromopyridines or benzo-fused homologs (Scheme 39), and has yielded a series of regioisomeric bipyridines (183). 3-Trimethylstannylquinoline reacts readily with 2-bromopyridine to furnish 184. 2,4-Distannylated pyridine can be coupled twice with 3-bromopyridine to form 185 (86S564). Coupling with 4-iodobenzoic acid ester proceeds equally well (186) (86TL4407). 

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