Polymer-bound haloate(I) anions by iodine(III)-mediated oxidation of polymer-bound iodide: Synthetic utility in natural product transformations

Abstract

A set of polymer-attached hypervalent iodate(I) complexes were prepared from polymer-bound iodide anion by ligand transfer of acetate and trifluoro acetate present in the corresponding iodine(III) reagents onto the iodide anion. The synthetic versatility of these polymer-bound reagents in terms of efficacy and ease of workup is demonstrated for selected examples in natural product synthesis and natural product derivatization. Thus, iodoacetoxylation of glycals is the initial step for the preparation of two deoxygenated disaccharides which are part of the carbohydrate units of the landomycins. In a second example, a one-pot multistep rearrangement of the decanolide decarestrictine D backbone is shown which is initiated by iodotrifluoroacylation of the olefinic double bond.

Fe2(SO4)3-mediated Coiodination of Alkenes with Acetic Acid: A Convenient and Regioselective Eco-friendly Preparation of β-iodoacetates

“…of I 2 and 1.2 mol equiv. of the Fe(III) salt in acetic acid at room temperature within 4.5-7.0 h. In all the reactions the purity of the isolated product (> 95%) was confirmed by 1 H and 13 C NMR and high-resolution gas chromatography (HRGC). The yields of the β-iodoacetates were good to excellent and the products were characterised by comparison of their spectral data with those previously reported.…”

“…Mass spectra were obtained on a Hewlett-Packard HP5896-A HRGC-MS using electron impact (70 eV). 1 H NMR and 13 C NMR spectra were acquired on a Bruker AC-200 (200 MHz and 50 MHz, respectively) spectrometer for CDCl 3 solutions with tetramethylsilane as internal standard. In all the reactions, the purity of the isolated product (> 95%) was confirmed by 1 H NMR, 13 C NMR, and HRGC analyses.…”

“…1 H NMR and 13 C NMR spectra were acquired on a Bruker AC-200 (200 MHz and 50 MHz, respectively) spectrometer for CDCl 3 solutions with tetramethylsilane as internal standard. In all the reactions, the purity of the isolated product (> 95%) was confirmed by 1 H NMR, 13 C NMR, and HRGC analyses. The reaction of alkenes with I 2 and Fe 2 (SO 4 ) 3 in acetic acid at room temperature produced the corresponding β-iodoacetates in 79-92% isolated yields and high regioselectivity.…”

“…4 Traditional methodologies for the 1,2-iodoacetoxylation of alkenes include the reaction of I 2 with an alkene in the presence of acetic acid mediated by diverse heavy metal salts such as Tl(I), 2 Ag(I), 3,4 Pb(II), 5 Bi(III), 6 Hg(II), 7 Ce(IV), 8 Cu(II), 9 Co(II) 10 or oxidising reagents. 11 Alternate methodologies are the reactions of alkenes with excess iodine and KOAc supported on Al 2 O 3 , 12 diacetoxyiodine(I) complexes 13 or in situ generated acyl hypoiodite, 14 and also the reactions with NIS 15 or Ipy 2 BF 4 16 in the presence of acetic acid. Recently, Chavan and Sharma published the intramolecular coiodination of unsaturated carboxylic acids to produce iodo-lactones mediated by catalytic FeCl 3 .…”

Oxidative Esterification of Aromatic Aldehydes Using Polymer-Supported Green Bromine

“…Application of polymer-supported reagents in organic synthesis has grown over the years due to the convenience in handling, easy workup procedures, and recyclability of the reagents. Polymer-supported iodate, 14 periodate, 15 bromate, 16 hypochlorite, and dichloroiodo resins, 17 used as oxidizing agents, have reported in the literature. However, there is no report on polymer-supported bromine chloride resin in oxidation reactions.…”